Migrate async tests to strong

tests/lib_strong/async/intercept_schedule_microtask4_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';
+
+var events = [];
+
+body() {
+  events.add("body entry");
+  scheduleMicrotask(() {
+    events.add("run async body");
+    scheduleMicrotask(() {
+      events.add("run nested body");
+    });
+  });
+  return 499;
+}
+
+handler(fun) {
+  events.add("handler");
+  scheduleMicrotask(fun);
+  events.add("handler done");
+}
+
+main() {
+  asyncStart();
+
+  // Test that body of a scheduleMicrotask goes to the zone it came from.
+  var result = runZonedScheduleMicrotask(body, onScheduleMicrotask: handler);
+  events.add("after");
+  scheduleMicrotask(() {
+    scheduleMicrotask(() {
+      Expect.listEquals(
+          ["body entry",
+           "handler", "handler done",
+           "after",
+           "run async body",
+           "handler", "handler done",
+           "run nested body"],
+          events);
+      asyncEnd();
+    });
+  });
+}