Migrate async tests to strong

tests/lib_strong/async/intercept_schedule_microtask1_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';
+
+main() {
+  // Test that runZoned returns the result of executing the body.
+  var result = runZonedScheduleMicrotask(() => 499,
+    onScheduleMicrotask: (f) {
+      Expect.fail("Unexpected invocation.");
+    });
+  Expect.equals(499, result);
+}