Revert of [telemetry] Refactor run_tests to remove old cruft.

tools/telemetry/run_tests

 #!/usr/bin/env python
 # 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.
 
 import os
 import sys
 
+from telemetry.unittest import gtest_testrunner
 from telemetry.unittest import run_tests
 
 
 if __name__ == '__main__':
-  base_dir = os.path.dirname(os.path.realpath(__file__))
-  run_tests.environment = run_tests.Environment(base_dir, [base_dir])
-  sys.exit(run_tests.RunTestsCommand.main())
+  top_level_dir = os.path.abspath(os.path.dirname(__file__))
+  runner = gtest_testrunner.GTestTestRunner(print_result_after_run=False)
+  ret = run_tests.Main(sys.argv[1:], top_level_dir, top_level_dir, runner)
+
+  if runner.result:
+    runner.result.PrintSummary()
+    sys.exit(min(ret + runner.result.num_errors, 255))
+  else:
+    sys.exit(ret)