Add asynchronous test suite runner to Dart rewrite of test scripts.

tools/test.dart

+#!/usr/bin/env dart_bin
+// Copyright (c) 2011, 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("test");
+
+#import("testing/dart/test_runner.dart");
+#import("../tests/standalone/test_config.dart");
+#import("../tests/corelib/test_config.dart");
+
+main() {
+  int numProcessors = new Platform().numberOfProcessors();
+  var queue = new ProcessQueue(numProcessors);
+  new StandaloneTestSuite().forEachTest(queue.runTest);
+  new CorelibTestSuite().forEachTest(queue.runTest);
+}