Making ScriptProcessorNode not an EventTarget.

tests/html/audiobuffersourcenode_test.dart

 library AudioBufferSourceNodeTest;
 import '../../pkg/unittest/lib/unittest.dart';
-import '../../pkg/unittest/lib/html_config.dart';
+import '../../pkg/unittest/lib/html_individual_config.dart';
 import 'dart:web_audio';
 
 main() {
 
-  useHtmlConfiguration();
+  useHtmlIndividualConfiguration();
 
-  test('createBuffer', () {
-      var ctx = new AudioContext();
-      AudioBufferSourceNode node = ctx.createBufferSource();
-      node.start(ctx.currentTime, 0, 2);
-      node.stop(ctx.currentTime + 2);
-      expect(node is AudioBufferSourceNode, isTrue);
+  group('supported', () {
+    test('supported', () {
+      expect(AudioContext.supported, true);
+    });
+  });
+
+  group('functional', () {
+    test('createBuffer', () {
+      if(AudioContext.supported) {
+        var ctx = new AudioContext();
+        AudioBufferSourceNode node = ctx.createBufferSource();
+        node.start(ctx.currentTime, 0, 2);
+        node.stop(ctx.currentTime + 2);
+        expect(node is AudioBufferSourceNode, isTrue);
+      }
+    });
   });
 }