Fix call to completer for async closures.

tests/language/async_control_structures_test.dart

 // Copyright (c) 2014, 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.
 
-// VMOptions=--enable_async
+// VMOptions=--enable_async --optimization-counter-threshold=10
 
 import 'package:expect/expect.dart';
 
 import 'dart:async';
 
 expectThenValue(future, value) {
   Expect.isTrue(future is Future);
   future.then((result) {
     Expect.equals(value, result);
   });
@@ skipping 44 matching lines @@
   }
 }
 
 asyncImplicitReturn() async {
   try {}
   catch (e) {}
   finally {}
 }
 
 main() {
   var asyncReturn;

[srdjan, 2014/08/13 16:49:33]

You can put this in a loop with 10 iterations to make sure that all functions
will be optimized.

[Michael Lippautz (Google), 2014/08/13 17:13:56]

Done.

 
   asyncReturn = asyncIf(true);
   expectThenValue(asyncReturn, 1);
   asyncReturn = asyncIf(false);
   expectThenValue(asyncReturn, 2);
 
   asyncReturn = asyncFor(true);
   expectThenValue(asyncReturn, 1);
   asyncReturn = asyncFor(false);
   expectThenValue(asyncReturn, 2);
 
   asyncReturn = asyncTryCatchFinally(true, false);
   expectThenValue(asyncReturn, 3);
   asyncReturn = asyncTryCatchFinally(false, false);
   expectThenValue(asyncReturn, 1);
   asyncReturn = asyncTryCatchFinally(true, true);
   expectThenValue(asyncReturn, 3);
   asyncReturn = asyncTryCatchFinally(false, true);
   expectThenValue(asyncReturn, 444);
   asyncReturn = asyncTryCatchLoop();
   expectThenValue(asyncReturn, 13);
 
   asyncReturn = asyncImplicitReturn();
   expectThenValue(asyncReturn, null);
 }