Removing window.console.log from js_custom_test

tests/html/custom/js_custom_test.dart

 // Copyright (c) 2013, 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 js_custom_test;
 
 import 'package:unittest/unittest.dart';
 import 'package:unittest/html_config.dart';
 import 'dart:html';
 import '../utils.dart';
@@ skipping 37 matching lines @@
 
     expect(a.attributes['fromJS'], 'true');
   });
 
   test('accessing custom JS element from Dart', () {
     var script = '''
     var Foo = document.register('x-foo', {
       prototype: Object.create(HTMLElement.prototype, {
         createdCallback: {
           value: function() {
-            window.console.log('Foo created!');
             this.setAttribute('fromJS', 'true');
           }
         }
       })});
     var foo = new Foo();
     foo.id = 'b';
     document.body.appendChild(foo);
     ''';
 
     document.body.append(new ScriptElement()..text = script);
     var custom = document.querySelector('#b');
     expect(custom is HtmlElement, isTrue);
     expect(custom.attributes['fromJS'], 'true');
   });
 }