Test for the correct class in AnimationPlayer.supported and fix Dartium suppressions

tests/html/element_animate_test.dart

 // Copyright (c) 2015, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library element_animate_test;
 
 import 'dart:async';
 import 'dart:html';
 import 'package:unittest/html_individual_config.dart';
 import 'package:unittest/unittest.dart';
 
 main() {
   useHtmlIndividualConfiguration();
 
   group('animate_supported', () {
     test('supported', () {
-      expect(Notification.supported, true);
+      expect(AnimationPlayer.supported, true);
     });
   });
 
   group('simple_timing', () {
     test('simple timing', () {
       var body = document.body;
       var opacity = num.parse(body.getComputedStyle().opacity);
       body.animate([{"opacity": 100}, {"opacity": 0}], 100);
       var newOpacity = num.parse(body.getComputedStyle().opacity);
       expect(newOpacity < opacity, isTrue);
@@ skipping 19 matching lines @@
     test('omit timing', () {
       var body = document.body;
       var player = body.animate([
         {"transform": "translate(100px, -100%)"},
         {"transform": "translate(400px, 500px)"}
       ]);
       player.on['finish'].listen(expectAsync((_) => 'done'));
     });
   });
 }