Add first version of runAsync.

tests/lib/async/run_async4_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.
+
+library run_async_test;
+
+import 'dart:async';
+import 'dart:isolate';
+
+void startTest(SendPort finishPort, replyPort) {
+  int invokedCallbacks = 0;
+
+  for (int i = 0; i < 100; i++) {
+    runAsync(() {
+      invokedCallbacks++;
+      if (invokedCallbacks == 100) finishPort.send("done");
+      if (i == 50) throw new RuntimeError("ignore exception");
+    });
+  }
+
+  // Without this Timer the isolate will freeze.
+  // TODO(9013): Remove this Timer.
+  new Timer(const Duration(seconds: 2), () { });
+}
+
+runTest() {
+  port.receive(startTest);
+}
+
+bool globalErrorHandler(IsolateUnhandledException e) {
+  return e.source is RuntimeError && e.source.message == "ignore exception";
+}
+
+main() {
+  var port = new ReceivePort();
+  SendPort otherIsolate = spawnFunction(runTest, globalErrorHandler);
+  otherIsolate.send(port.toSendPort());
+  port.receive((msg, replyPort) { port.close(); });
+}