Run dartfmt on remaining unformated pkg packages

pkg/async_helper/lib/async_helper.dart

 // Copyright (c) 2013, 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.
 
 /// This library is used for testing asynchronous tests.
 /// If a test is asynchronous, it needs to notify the testing driver
 /// about this (otherwise tests may get reported as passing [after main()
 /// finished] even if the asynchronous operations fail).
 /// Tests which can't use the unittest framework should use the helper functions
 /// in this library.
@@ skipping 23 matching lines @@
 int _asyncLevel = 0;
 
 Exception _buildException(String msg) {
   return new Exception('Fatal: $msg. This is most likely a bug in your test.');
 }
 
 /// Call this method before an asynchronous test is created.
 void asyncStart() {
   if (_initialized && _asyncLevel == 0) {
     throw _buildException('asyncStart() was called even though we are done '
-                          'with testing.');
+        'with testing.');
   }
   if (!_initialized) {
     print('unittest-suite-wait-for-done');
     _initialized = true;
     _port = new ReceivePort();
   }
   _asyncLevel++;
 }
 
 /// Call this after an asynchronous test has ended successfully.
 void asyncEnd() {
   if (_asyncLevel <= 0) {
     if (!_initialized) {
       throw _buildException('asyncEnd() was called before asyncStart().');
     } else {
       throw _buildException('asyncEnd() was called more often than '
-                            'asyncStart().');
+          'asyncStart().');
     }
   }
   _asyncLevel--;
   if (_asyncLevel == 0) {
     _port.close();
     _port = null;
     print('unittest-suite-success');
   }
 }
 
@@ skipping 13 matching lines @@
 
 /**
  * Helper method for performing asynchronous tests involving [:Future:].
  *
  * [f] must return a [:Future:] for the test computation.
  */
 void asyncTest(f()) {
   asyncStart();
   f().then(asyncSuccess);
 }