Added GPU stress test with multiple tabs in one single window.

tools/gpu_validation/run_gpu_validation_tests

Index: tools/gpu_validation/run_gpu_validation_tests
diff --git a/tools/telemetry/run_tests b/tools/gpu_validation/run_gpu_validation_tests
similarity index 78%
copy from tools/telemetry/run_tests
copy to tools/gpu_validation/run_gpu_validation_tests
index 50d20acd0444953073ae14ce26c693974c3f57e6..a18801cbdd426160638ec4115173d55f2199f2f1 100755
--- a/tools/telemetry/run_tests
+++ b/tools/gpu_validation/run_gpu_validation_tests
@@ -2,17 +2,20 @@
 # Copyright (c) 2012 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.
+
+"""This script runs tests to verify that the GPU is working properly."""
+
 import os
 import sys
 
+import tests
 from telemetry.test import gtest_testrunner
 from telemetry.test import run_tests
 
 if __name__ == '__main__':
   top_level_dir = os.path.abspath(os.path.dirname(__file__))
   runner = gtest_testrunner.GTestTestRunner(print_result_after_run=False)
-  start_dir = 'telemetry'
-  ret = run_tests.Main(sys.argv[1:], start_dir, top_level_dir, runner)
+  ret = run_tests.Main(sys.argv[1:], 'tests', top_level_dir, runner)
 
   if runner.result:
     runner.result.PrintSummary()