Make a generic third_party/closure_compiler/run_tests.py that runs more

unit tests on each continous build.

build/ CL: https://codereview.chromium.org/1128313003

R=tbreisacher@chromium.org
BUG=393873

NOTRY=true

Review URL: https://codereview.chromium.org/1137933003

Cr-Commit-Position: refs/heads/master@{#329450}

third_party/closure_compiler/run_tests.py

+#!/usr/bin/env python
+# Copyright 2015 The Chromium Authors. All rights reserved.
+# Use of this source code is governed by a BSD-style license that can be
+# found in the LICENSE file.
+
+
+import compiler_customization_test
+import processor_test
+
+
+for test_module in [compiler_customization_test, processor_test]:
+  test_module.unittest.main(test_module)