Add a complex reload test that rebases the root script path three times.

runtime/observatory/tests/service/complex_reload/v3/main.dart

Index: runtime/observatory/tests/service/complex_reload/v3/main.dart
diff --git a/runtime/observatory/tests/service/complex_reload/v3/main.dart b/runtime/observatory/tests/service/complex_reload/v3/main.dart
new file mode 100644
index 0000000000000000000000000000000000000000..751ca9656d2b42aeb17a1f98cda1e84dc27fdd8c
--- /dev/null
+++ b/runtime/observatory/tests/service/complex_reload/v3/main.dart
@@ -0,0 +1,6 @@
+// Copyright (c) 2016, 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.
+// VMOptions=--error_on_bad_type --error_on_bad_override
+
+test() => 'cabbage';