Revert "Remove Expect from core library."

tests/corelib/queue_test.dart

 // Copyright (c) 2011, 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 queue.test;
 
-import "package:expect/expect.dart";
 import 'dart:collection';
 
 abstract class QueueTest {
 
   Queue newQueue();
   Queue newQueueFrom(Iterable iterable);
 
   void testMain() {
     Queue queue = newQueue();
     checkQueue(queue, 0, 0);
@@ skipping 321 matching lines @@
   q.addAll(i255.skip(35).take(96));
   q.addAll(i255.skip(35 + 96));
   Expect.listEquals(i255.toList(), q.toList());
 }
 
 main() {
   new DoubleLinkedQueueTest().testMain();
   new ListQueueTest().testMain();
   trickyTest();
 }