Start cleaning up the HTML tests.

pkg/dev_compiler/test/codegen/lib/html/audiocontext_test.dart

-library AudioContextTest;
-import 'package:unittest/unittest.dart';
-import 'package:unittest/html_individual_config.dart';
+import 'dart:async';
 import 'dart:html';
 import 'dart:typed_data';
 import 'dart:web_audio';
-import 'dart:async';
+
+import 'package:minitest/minitest.dart';
 
 main() {
-
-  useHtmlIndividualConfiguration();
-
   var isAudioContext =
       predicate((x) => x is AudioContext, 'is an AudioContext');
 
   group('supported', () {
     test('supported', () {
       expect(AudioContext.supported, true);
     });
   });
 
   group('functional', () {
     var context;
     if (AudioContext.supported) {
       context = new AudioContext();
     }
-    
+
     test('constructorTest', () {
-      if(AudioContext.supported) {
+      if (AudioContext.supported) {
         expect(context, isNotNull);
         expect(context, isAudioContext);
       }
     });
 
     test('audioRenames', () {
-      if(AudioContext.supported) {
+      if (AudioContext.supported) {
         GainNode gainNode = context.createGain();
         gainNode.connectNode(context.destination);
         expect(gainNode is GainNode, isTrue);
 
         expect(context.createAnalyser() is AnalyserNode, isTrue);
         expect(context.createChannelMerger() is AudioNode, isTrue);
         expect(context.createChannelSplitter() is AudioNode, isTrue);
         expect(context.createOscillator() is OscillatorNode, isTrue);
         expect(context.createPanner() is PannerNode, isTrue);
         expect(context.createScriptProcessor(4096) is ScriptProcessorNode,
@@ skipping 43 matching lines @@
         expect(oscillator.type, equals('triangle'));
 
         // Firefox does not throw when it receives invalid values; it simply
         // ignores them.
         //expect(() => oscillator.type = ['heap object not a string'], throws);
         expect(oscillator.type, equals('triangle'));
       }
     });
   });
 }