Revert "Switch libraries to using new tags."

sdk/lib/core/queue.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.
 
-part of dart_core;
-
 /**
  * A [Queue] is a collection that can be manipulated at both ends. One
  * can iterate over the elements of a queue through [forEach] or with
  * an [Iterator].
  */
 abstract class Queue<E> extends Collection<E> {
 
   /**
    * Creates a queue.
    */
@@ skipping 314 matching lines @@
   }
 
   E next() {
     if (!hasNext) {
       throw new StateError("No more elements");
     }
     _currentEntry = _currentEntry._next;
     return _currentEntry.element;
   }
 }