Re-apply 'Unify dart:isolate.' with fixes for autogenerated dart2js and dartium html files.

lib/js_isolate_impl/isolate.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.
 
+// Patch file for the dart:isolate library.
+
+/********************************************************
+  Inserted from lib/isolate/serialization.dart
+ ********************************************************/
+
 class _MessageTraverserVisitedMap {
 
   operator[](var object) => null;
   void operator[]=(var object, var info) { }
 
   void reset() { }
   void cleanup() { }
 
 }
 
@@ skipping 182 matching lines @@
     return result;
   }
 
   abstract deserializeSendPort(List x);
 
   deserializeObject(List x) {
     // TODO(floitsch): Use real exception (which one?).
     throw "Unexpected serialized object";
   }
 }
+