Upgrading tests with unittest deprecations

tests/lib/async/stream_periodic5_test.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.
 
 // Test merging streams.
 library dart.test.stream_from_iterable;
 
 import "dart:async";
 import '../../../pkg/unittest/lib/unittest.dart';
 
@@ skipping 21 matching lines @@
         // Make sure the stream can be paused when it has overdue events.
         // We just busy waited for 15ms, even though the stream is supposed to
         // emit events every 5ms.
         subscription.pause();
         watch.stop();
         new Timer(const Duration(milliseconds: 150), () {
           watch.start();
           subscription.resume();
         });
       } 
-    }, onDone: expectAsync0(() { }));
+    }, onDone: expectAsync(() { }));
   });
 }