Move timer tests to async tests.

tests/lib/async/multiple_timer_test.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.
 
 library multiple_timer_test;
 
 import 'dart:async';
-import '../../pkg/unittest/lib/unittest.dart';
+import '../../../pkg/unittest/lib/unittest.dart';
 
 const Duration TIMEOUT1 = const Duration(seconds: 1);
 const Duration TIMEOUT2 = const Duration(seconds: 2);
 const Duration TIMEOUT3 = const Duration(milliseconds: 500);
 const Duration TIMEOUT4 = const Duration(milliseconds: 1500);
 
 main() {
   test("multiple timer test", () {
     Stopwatch _stopwatch1 = new Stopwatch();
     Stopwatch _stopwatch2 = new Stopwatch();
@@ skipping 48 matching lines @@
     _stopwatch1.start();
     new Timer(TIMEOUT1, expectAsync0(timeoutHandler1));
     _stopwatch2.start();
     new Timer(TIMEOUT2, expectAsync0(timeoutHandler2));
     _stopwatch3.start();
     new Timer(TIMEOUT3, expectAsync0(timeoutHandler3));
     _stopwatch4.start();
     new Timer(TIMEOUT4, expectAsync0(timeoutHandler4));
   });
 }