Fix async test failures

sdk/lib/async/future_impl.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.
 
 part of dart.async;
 
 /** The onValue and onError handlers return either a value or a future */
 typedef dynamic/*T|Future<T>*/ _FutureOnValue<S, T>(S value);
 /** Test used by [Future.catchError] to handle skip some errors. */
 typedef bool _FutureErrorTest(var error);
@@ skipping 609 matching lines @@
             var originalSource = source;
             listenerValueOrError = completeResult.then((_) => originalSource);
             listenerHasError = false;
           }
         }
 
         void handleValueCallback() {
           try {
             listenerValueOrError = listener.handleValue(sourceResult);
           } catch (e, s) {
-            if (identical(source._error.error, e)) {
-              listenerValueOrError = source._error;
-            } else {
-              listenerValueOrError = new AsyncError(e, s);
-            }
+            listenerValueOrError = new AsyncError(e, s);
             listenerHasError = true;
           }
         }
 
         void handleError() {
           try {
             AsyncError asyncError = source._error;
             if (listener.matchesErrorTest(asyncError) &&
                 listener.hasErrorCallback) {
               listenerValueOrError = listener.handleError(asyncError);
@@ skipping 87 matching lines @@
       }
     }, onError: (e, s) {
       if (timer.isActive) {
         timer.cancel();
         result._completeError(e, s);
       }
     });
     return result;
   }
 }