Fixing the NativeAOT field layout tests

Author: tannergooding

src/coreclr/tools/aot/ILCompiler.TypeSystem.Tests/CoreTestAssembly/Platform.cs

@@ -182,4 +182,22 @@ public readonly struct Vector128<T>
         private readonly ulong _00;
         private readonly ulong _01;
     }
+
+    [Intrinsic]
+    [StructLayout(LayoutKind.Sequential, Size = 32)]
+    public readonly struct Vector256<T>
+        where T : struct
+    {
+        private readonly Vector128<T> _lower;
+        private readonly Vector128<T> _upper;
+    }
+
+    [Intrinsic]
+    [StructLayout(LayoutKind.Sequential, Size = 64)]
+    public readonly struct Vector512<T>
+        where T : struct
+    {
+        private readonly Vector256<T> _lower;
+        private readonly Vector256<T> _upper;
+    }
 }

src/coreclr/tools/aot/ILCompiler.TypeSystem.Tests/InstanceFieldLayoutTests.cs

@@ -893,7 +893,7 @@ public void TestAutoTypeLayoutClass32Align()
         }
 
         [Fact]
-        public void TestAutoTypeLayoutClass16Align()
+        public void TestAutoTypeLayoutClass64Align()
         {
             MetadataType classType = _testModule.GetType("Auto", "Class64Align");
             Assert.Equal(0x48, classType.InstanceByteCount.AsInt);