Move some core classes to collection library.

sdk/lib/_internal/compiler/implementation/lib/isolate_helper.dart

 // Copyright (c) 2012, 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 _isolate_helper;
 
 import 'dart:async';
+import 'dart:collection' show Queue, HashMap;
 import 'dart:isolate';
 
 ReceivePort lazyPort;
 
 /**
  * Called by the compiler to support switching
  * between isolates when we get a callback from the DOM.
  */
 void _callInIsolate(_IsolateContext isolate, Function function) {
   isolate.eval(function);
@@ skipping 1310 matching lines @@
         JS('void', '#.clearInterval(#)', globalThis, _handle);
       }
       _handle = null;
     } else {
       throw new UnsupportedError("Canceling a timer.");
     }
   }
 }
 
 bool hasTimer() => JS('', '#.setTimeout', globalThis) != null;