Add first version of runAsync.

tests/lib/async/run_async_test.dart

Index: tests/lib/async/run_async_test.dart
diff --git a/tests/compiler/dart2js_extra/deferred/deferred_semantics_test.dart b/tests/lib/async/run_async_test.dart
similarity index 58%
copy from tests/compiler/dart2js_extra/deferred/deferred_semantics_test.dart
copy to tests/lib/async/run_async_test.dart
index 140faca3f8479b47e297b51ee4201a0a9f928b31..0ec7afae1fa6b2c289bc09a3c4fe067f382c0896 100644
--- a/tests/compiler/dart2js_extra/deferred/deferred_semantics_test.dart
+++ b/tests/lib/async/run_async_test.dart
@@ -2,14 +2,13 @@
 // 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 that deferred loading requires same library names.
+library run_async_test;
 
 import 'dart:async';
-
-@lazy  /// 01: compile-time error
-import 'deferred_function_library.dart';
-
-const lazy = const DeferredLibrary('fisk');
+import '../../../pkg/unittest/lib/unittest.dart';
 
 main() {
+  test("run async test", () {
+    runAsync(expectAsync0(() {}));
+  });
 }