pkg/polymer[_expressions] unittest fixes

pkg/polymer/test/bind_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.
 
 import 'dart:async';
 import 'dart:html';
 import 'package:polymer/polymer.dart';
 import 'package:unittest/unittest.dart';
 import 'package:unittest/html_config.dart';
-import 'package:unittest/matcher.dart';
 
 @CustomTag('x-bar')
 class XBar extends PolymerElement {
   XBar.created() : super.created();
 
   get testValue => true;
 }
 
 @CustomTag('x-foo')
 class XFoo extends PolymerElement {
@@ skipping 24 matching lines @@
 }
 
 @initMethod
 main() {
   useHtmlConfiguration();
 
   setUp(() => Polymer.onReady);
 
   test('ready called', () => (querySelector('x-foo') as XFoo).onTestDone);
 }