Migrate html tests using async_minitest and minitest

Move them to async_minitest.

Change-Id: Ibe850b05a838dd64ae62b30c9a979de371b24db6
Reviewed-on: https://dart-review.googlesource.com/c/sdk/+/138741
Commit-Queue: Srujan Gaddam <[email protected]>
Reviewed-by: Bob Nystrom <[email protected]>

Author: srujzs

tests/lib_2/html/fileapi_supported_test.dart

@@ -5,7 +5,6 @@ import 'dart:html';
 
 import 'package:async_helper/async_helper.dart';
 import 'package:async_helper/async_minitest.dart';
-import 'package:expect/minitest.dart' as minitest;
 
 
 Future<FileSystem> _fileSystem;
@@ -30,8 +29,8 @@ main() {
   });
 
   test('requestFileSystem', () async {
-    var expectation = FileSystem.supported ? minitest.returnsNormally : throws;
-    minitest.expect(() async {
+    var expectation = FileSystem.supported ? returnsNormally : throws;
+    expect(() async {
       var fs = await fileSystem;
       expect(fs.root != null, true);
     }, expectation);

tests/lib_2/html/websocket_test.dart

@@ -3,7 +3,6 @@ library WebSocketTest;
 import 'dart:html';
 
 import 'package:async_helper/async_minitest.dart';
-import 'package:expect/minitest.dart' as minitest;
 
 main() {
   group('supported', () {
@@ -13,15 +12,13 @@ main() {
   });
 
   group('websocket', () {
-    var isWebSocket =
-        minitest.predicate((x) => x is WebSocket, 'is a WebSocket');
-    var expectation = WebSocket.supported ? minitest.returnsNormally : throws;
+    var expectation = WebSocket.supported ? returnsNormally : throws;
 
     test('constructorTest', () {
-      minitest.expect(() {
+      expect(() {
         var socket = new WebSocket('ws://localhost/ws', 'chat');
         expect(socket, isNotNull);
-        minitest.expect(socket, isWebSocket);
+        expect(socket, isInstanceOf<WebSocket>());
       }, expectation);
     });