Migrated test block 170 to Dart 2.0.

tests/lib/async/intercept_schedule_microtask2_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:expect/expect.dart";
-import 'dart:async';
-import 'catch_errors.dart';
-
-var events = [];
-
-body() {
-  events.add("body entry");
-  scheduleMicrotask(() {
-    events.add("run async body");
-  });
-  return 499;
-}
-
-handler(fun) {
-  events.add("handler");
-  fun();
-  events.add("handler done");
-}
-
-main() {
-  // Test that scheduleMicrotask interception works.
-  var result = runZonedScheduleMicrotask(body, onScheduleMicrotask: handler);
-  // No need for a ReceivePort: If the runZonedScheduleMicrotask misbehaved we
-  // would have an [events] list that is different from what we expect.
-  Expect.listEquals(
-      ["body entry", "handler", "run async body", "handler done"], events);
-}