isolates in frog: playing with API improvements

tests/isolate/src/APIv2_spawnStandaloneTest.dart

+// Copyright (c) 2012, 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.
+
+// example of spawning an isolate from a closure
+#library('spawn_tests');
+
+child(ReceivePort port) {
+  port.receive((msg, reply) => reply.send("re: $msg"));
+}
+
+main() {
+  ReceivePort port = new ReceivePort();
+  port.receive((msg, _) {
+    Expect.equals("re: hi", msg);
+    port.close();
+  });
+
+  Isolate2 c = new Isolate2.fromCode(child);
+  c.sendPort.send("hi", port.toSendPort());
+}