Use u8 in more places (#69995)

* Use u8 in more places

Primarily replacing Encoding.UTF8/ASCII.GetBytes("literal") with "literal"u8.ToArray()

* Address PR feedback (and fix some vars)

Author: stephentoub

src/libraries/Common/tests/StreamConformanceTests/System/IO/StreamConformanceTests.cs

@@ -1855,7 +1855,7 @@ public virtual async Task Read_Eof_Returns0(ReadWriteMode mode, bool dataAvailab
             {
                 write = Task.Run(async () =>
                 {
-                    await writeable.WriteAsync(Encoding.UTF8.GetBytes("hello"));
+                    await writeable.WriteAsync("hello"u8.ToArray());
                     await writeable.DisposeAsync();
                 });
             }
@@ -2206,7 +2206,7 @@ public virtual async Task ZeroByteRead_BlocksUntilDataAvailableOrNops(ReadWriteM
 
                         Task write = Task.Run(async () =>
                         {
-                            await writeable.WriteAsync(Encoding.UTF8.GetBytes("hello"));
+                            await writeable.WriteAsync("hello"u8.ToArray());
                             if (FlushRequiredToWriteData)
                             {
                                 if (FlushGuaranteesAllDataWritten)
@@ -2261,7 +2261,7 @@ public virtual async Task ZeroByteRead_BlocksUntilDataAvailableOrNops(ReadWriteM
         [SkipOnPlatform(TestPlatforms.LinuxBionic, "SElinux blocks UNIX sockets")]
         public virtual async Task ZeroByteWrite_OtherDataReceivedSuccessfully(ReadWriteMode mode)
         {
-            byte[][] buffers = new[] { Array.Empty<byte>(), Encoding.UTF8.GetBytes("hello"), Array.Empty<byte>(), Encoding.UTF8.GetBytes("world") };
+            byte[][] buffers = new[] { Array.Empty<byte>(), "hello"u8.ToArray(), Array.Empty<byte>(), "world"u8.ToArray() };
 
             using StreamPair streams = await CreateConnectedStreamsAsync();
             foreach ((Stream writeable, Stream readable) in GetReadWritePairs(streams))
@@ -2915,7 +2915,7 @@ public virtual async Task ZeroByteRead_PerformsZeroByteReadOnUnderlyingStreamWhe
             // (a) produce at least two readable bytes, so we can unblock the reader and read a single byte without clearing its buffer; and
             // (b) produce no more than 1K of readable bytes, so we can clear the reader buffer below.
             // If this isn't the case for some Stream(s), we can modify the data or parameterize it per Stream.
-            byte[] data = Encoding.UTF8.GetBytes("hello world");
+            byte[] data = "hello world"u8.ToArray();
 
             using StreamPair innerStreams = ConnectedStreams.CreateBidirectional();
             (Stream innerWriteable, Stream innerReadable) = GetReadWritePair(innerStreams);

src/libraries/Common/tests/System/Net/Http/Http2LoopbackConnection.cs

@@ -100,7 +100,7 @@ private async Task ReadPrefixAsync()
                 // Since those tests are not set up to handle multiple retries, we instead just send back an invalid response here
                 // so that SocketsHttpHandler will not induce retry.
                 // The contents of what we send don't really matter, as long as it is interpreted by SocketsHttpHandler as an invalid response.
-                await _connectionStream.WriteAsync(Encoding.ASCII.GetBytes("HTTP/2.0 400 Bad Request\r\n\r\n"));
+                await _connectionStream.WriteAsync("HTTP/2.0 400 Bad Request\r\n\r\n"u8.ToArray());
                 _connectionSocket.Shutdown(SocketShutdown.Send);
                 // If WinHTTP doesn't support streaming a request without a length then it will fallback
                 // to HTTP/1.1. Throwing an exception to detect this case in WinHttpHandler tests. 

src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/DSA/DSAKeyFileTests.cs

@@ -182,7 +182,7 @@ public static void ReadWriteDsa1024EncryptedPkcs8_PasswordBytes()
 qE3Db1UI4anCCnyEj/jDA8R6hZTFDjxu6bG0Z66g7I2GBDEYaaB+8x0vtiyu5LXo
 6UZ53SX6S+jfIqJoF5YME9zVMoO2kwS/EGvc64+epCGcee1Nx4SGgUcr5HJYz1P4
 CU+l4wPQR0rRmYHIJJIvFh5OXk84pV0crsOrekw7tHeNU6DMzw==",
-                Encoding.UTF8.GetBytes("Password > cipher"),
+                "Password > cipher"u8.ToArray(),
                 new PbeParameters(
                     PbeEncryptionAlgorithm.Aes192Cbc,
                     HashAlgorithmName.SHA256,

src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/DSA/DSAKeyPemTests.cs

@@ -287,7 +287,7 @@ public static void ImportFromEncryptedPem_Pkcs8_Encrypted_Byte_Simple()
 xTL6VO9mx52x6h5WDAQAisMVeMkBoxQUWLANXiw1zSfVbsmB7mDknsRcvD3tcgMs
 7YLD7LQMiPAIjDlOP8XP/w==
 -----END ENCRYPTED PRIVATE KEY-----";
-                byte[] passwordBytes = Encoding.UTF8.GetBytes("test");
+                byte[] passwordBytes = "test"u8.ToArray();
                 dsa.ImportFromEncryptedPem(pem, passwordBytes);
                 DSAParameters dsaParameters = dsa.ExportParameters(true);
 
@@ -319,9 +319,8 @@ public static void ImportFromEncryptedPem_Pkcs8_Encrypted_AmbiguousPem()
 dVYwfovccu8ktEAwk5XAOo0r+5CCw2lDDw/hbDeO87BToC5Cc5nu3F5LxAUj8Flc
 v8pi3w==
 -----END ENCRYPTED PRIVATE KEY-----";
-                byte[] passwordBytes = Encoding.UTF8.GetBytes("test");
                 ArgumentException ae = AssertExtensions.Throws<ArgumentException>("input", () =>
-                    dsa.ImportFromEncryptedPem(pem, passwordBytes));
+                    dsa.ImportFromEncryptedPem(pem, "test"u8));
                 Assert.Contains(AmbiguousExceptionMarker, ae.Message);
             }
         }
@@ -332,9 +331,8 @@ public static void ImportFromEncryptedPem_Pkcs8_Byte_NoPem()
             using (DSA dsa = DSAFactory.Create())
             {
                 string pem = "";
-                byte[] passwordBytes = Encoding.UTF8.GetBytes("test");
                 ArgumentException ae = AssertExtensions.Throws<ArgumentException>("input", () =>
-                    dsa.ImportFromEncryptedPem(pem, passwordBytes));
+                    dsa.ImportFromEncryptedPem(pem, "test"u8));
                 Assert.Contains(NoPemExceptionMarker, ae.Message);
             }
         }

src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/DSA/DSATestData.cs

@@ -171,7 +171,7 @@ internal static void GetDSA1024_186_2(out DSAParameters parameters, out byte[] s
                 "41e2345f1f56df2458f426d155b4ba2db6dcd8c8"
                 ).HexToByteArray();
 
-            data = Encoding.ASCII.GetBytes("abc");
+            data = "abc"u8.ToArray();
         }
     }
 }

src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/EC/ECKeyFileTests.LimitedPrivate.cs

@@ -83,7 +83,7 @@ public void ReadNistP521EncryptedPkcs8_Pbes2_Aes128_LimitedPrivateKey_PasswordBy
 
             ReadWriteBase64EncryptedPkcs8(
                 base64,
-                Encoding.UTF8.GetBytes("qwerty"),
+                "qwerty"u8.ToArray(),
                 new PbeParameters(
                     PbeEncryptionAlgorithm.Aes256Cbc,
                     HashAlgorithmName.SHA1,

src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/EC/ECKeyFileTests.cs

@@ -195,7 +195,7 @@ public void ReadNistP521EncryptedPkcs8_Pbes2_Aes128_Sha384_PasswordBytes()
 
             ReadWriteBase64EncryptedPkcs8(
                 base64,
-                Encoding.UTF8.GetBytes("qwerty"),
+                "qwerty"u8.ToArray(),
                 new PbeParameters(
                     PbeEncryptionAlgorithm.Aes256Cbc,
                     HashAlgorithmName.SHA1,

src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/EC/ECKeyPemTests.cs

@@ -342,8 +342,7 @@ public void ImportFromEncryptedPem_Pkcs8_Byte_Simple()
 /OMt/tWvtMSj17+dJvShsu/NYJXF5fsfpSJbd3e50Y3AisW0Ob7mmF54KBfg6Y+4
 aATwwQdUIKVzUZsQctsHPjbriQKKn7GKSyUOikBUNQ+TozojX8/g7JAsl+T9jGM=
 -----END ENCRYPTED PRIVATE KEY-----";
-                byte[] passwordBytes = Encoding.UTF8.GetBytes("test");
-                key.ImportFromEncryptedPem(pem, passwordBytes);
+                key.ImportFromEncryptedPem(pem, "test"u8);
                 ECParameters ecParameters = key.ExportParameters(true);
                 ECParameters expected = EccTestData.GetNistP256ReferenceKey();
                 EccTestBase.AssertEqual(expected, ecParameters);
@@ -370,10 +369,9 @@ public void ImportFromEncryptedPem_AmbiguousPem_Byte()
 opSAJ/pvHONL5kyAJLeNyG9c/mR2qyrP2L9gL0Z5fB9NyPejKTLi0PXMGQWdDTH8
 Qh0fqdrNovgFLubbJFMQN/MwwIAfIuf0Mn0WFYYeQiBJ3kg=
 -----END ENCRYPTED PRIVATE KEY-----";
-                byte[] passwordBytes = Encoding.UTF8.GetBytes("test");
 
                 ArgumentException ae = AssertExtensions.Throws<ArgumentException>("input", () =>
-                    key.ImportFromEncryptedPem(pem, passwordBytes));
+                    key.ImportFromEncryptedPem(pem, "test"u8));
 
                 Assert.Contains(AmbiguousExceptionMarker, ae.Message);
             }

src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/ECDsa/ECDsaTests.cs

@@ -274,8 +274,6 @@ public static IEnumerable<object[]> InteroperableSignatureConfigurations()
         [MemberData(nameof(InteroperableSignatureConfigurations))]
         public void SignVerify_InteroperableSameKeys_RoundTripsUnlessTampered(ECDsa ecdsa, HashAlgorithmName hashAlgorithm)
         {
-            byte[] data = Encoding.UTF8.GetBytes("something to repeat and sign");
-
             // large enough to make hashing work though multiple iterations and not a multiple of 4KB it uses.
             byte[] dataArray = new byte[33333];
 

src/libraries/Common/tests/System/Security/Cryptography/AlgorithmImplementations/RSA/RSAKeyFileTests.cs

@@ -781,7 +781,7 @@ public static void ReadPbes2Rc2EncryptedDiminishedDP_PasswordBytes()
 
             ReadBase64EncryptedPkcs8(
                 base64,
-                Encoding.UTF8.GetBytes("rc2"),
+                "rc2"u8.ToArray(),
                 new PbeParameters(
                     PbeEncryptionAlgorithm.Aes192Cbc,
                     HashAlgorithmName.SHA256,