isolate: fix how we get the current script now that frog automatically wraps the

tests/isolate/src/APIv2_computeThisScriptBrowserTest.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.
+
+// Test that spawn works even when there are many script files in the page.
+// This requires computing correctly the URL to the orignal script, so we can
+// pass it to the web worker APIs.
+#library('spawn_tests');
+#import('../../../lib/unittest/unittest_dom.dart');
+#import('dart:dom'); // import added so test.dart can treat this as a webtest.
+#import('dart:isolate');
+
+child() {
+  port.receive((msg, reply) => reply.send('re: $msg'));
+}
+
+main() {
+  var script = document.createElement('script');
+  document.body.appendChild(script);
+  asyncTest('spawn with other script tags in page', 1, () {
+    ReceivePort port = new ReceivePort();
+    port.receive((msg, _) {
+      expect(msg).equals('re: hi');
+      port.close();
+      callbackDone();
+    });
+
+    SendPort s = spawnFunction(child);
+    s.send('hi', port.toSendPort());
+  });
+}