Rename runAsync to scheduleMicrotask.

tests/lib/async/catch_errors27_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.
 
 import 'package:async_helper/async_helper.dart';
 import "package:expect/expect.dart";
 import 'dart:async';
 import 'catch_errors.dart';
 
 main() {
@@ skipping 13 matching lines @@
       stream = controller.stream
         .map((x) {
           events.add("map $x");
           return x + 100;
         })
         .asBroadcastStream();
       stream
         .transform(new StreamTransformer.fromHandlers(
             handleError: (e, st, sink) { sink.add("error $e"); }))
         .listen((x) { events.add("stream $x"); });
-      runAsync(() {
+      scheduleMicrotask(() {
         controller.add(1);
         // Errors are not allowed to traverse boundaries, but in this case the
         // first listener of the broadcast stream is in the same error-zone. So
         // this should work.
         controller.addError(2);
         controller.close();
       });
     }).listen((x) {
                 events.add(x);
                 if (x == 2) done.complete(true);
@@ skipping 10 matching lines @@
                           "stream 101",
                           "stream2 101",
                           "stream error 2",
                           2, // Caught by the inner `catchErrors`.
                         ],
                         events);
       asyncEnd();
     });
   });
 }