Add test_runner.dart to Dart version of test scripts. Include TestRunnerTest unit test.

tests/standalone/src/PassTest.dart

Index: tests/standalone/src/PassTest.dart
diff --git a/tests/standalone/src/PassTest.dart b/tests/standalone/src/PassTest.dart
new file mode 100644
index 0000000000000000000000000000000000000000..a0c15844db972ef3732f9ba77a4bd244963a029d
--- /dev/null
+++ b/tests/standalone/src/PassTest.dart
@@ -0,0 +1,9 @@
+// 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.
+
+
+// A test that passes.
+void main() {
+  print("This goes to stdout");
+}