[test] Remove default for zero test cases.

tools/run-tests.py

 #!/usr/bin/env python
 #
 # Copyright 2012 the V8 project authors. All rights reserved.
 # Redistribution and use in source and binary forms, with or without
 # modification, are permitted provided that the following conditions are
 # met:
 #
 #     * Redistributions of source code must retain the above copyright
 #       notice, this list of conditions and the following disclaimer.
 #     * Redistributions in binary form must reproduce the above
@@ skipping 566 matching lines @@
     for t in s.tests:
       t.id = test_id
       test_id += 1
 
   if options.cat:
     return 0  # We're done here.
 
   if options.report:
     verbose.PrintReport(all_tests)
 
-  if num_tests == 0:
-    print "No tests to run."
-    return 0
-
   # Run the tests, either locally or distributed on the network.
   start_time = time.time()
   progress_indicator = progress.PROGRESS_INDICATORS[options.progress]()
   if options.junitout:
     progress_indicator = progress.JUnitTestProgressIndicator(
         progress_indicator, options.junitout, options.junittestsuite)
   if options.json_test_results:
     progress_indicator = progress.JsonTestProgressIndicator(
         progress_indicator, options.json_test_results, arch,
         MODES[mode]["execution_mode"])
@@ skipping 26 matching lines @@
   exit_code = runner.Run(options.j)
   overall_duration = time.time() - start_time
 
   if options.time:
     verbose.PrintTestDurations(suites, overall_duration)
   return exit_code
 
 
 if __name__ == "__main__":
   sys.exit(Main())