Add --download-data-only option to run-test.py

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 188 matching lines @@
                     help="Regard pass|fail tests (run|skip|dontcare)",
                     default="dontcare")
   result.add_option("--gc-stress",
                     help="Switch on GC stress mode",
                     default=False, action="store_true")
   result.add_option("--command-prefix",
                     help="Prepended to each shell command used to run a test",
                     default="")
   result.add_option("--download-data", help="Download missing test suite data",
                     default=False, action="store_true")
+  result.add_option("--download-data-only",
+                    help="Download missing test suite data and exit",
+                    default=False, action="store_true")
   result.add_option("--extra-flags",
                     help="Additional flags to pass to each test command",
                     default="")
   result.add_option("--isolates", help="Whether to test isolates",
                     default=False, action="store_true")
   result.add_option("-j", help="The number of parallel tasks to run",
                     default=0, type="int")
   result.add_option("-m", "--mode",
                     help="The test modes in which to run (comma-separated)",
                     default="release,debug")
@@ skipping 259 matching lines @@
       args_suites[arg.split(os.path.sep)[0]] = True
     suite_paths = [ s for s in args_suites if s in suite_paths ]
 
   suites = []
   for root in suite_paths:
     suite = testsuite.TestSuite.LoadTestSuite(
         os.path.join(workspace, "test", root))
     if suite:
       suites.append(suite)
 
-  if options.download_data:
+  if options.download_data or options.download_data_only:
     for s in suites:
       s.DownloadData()
 
+  if options.download_data_only:
+    return exit_code
+
   for (arch, mode) in options.arch_and_mode:
     try:
       code = Execute(arch, mode, args, options, suites, workspace)
     except KeyboardInterrupt:
       return 2
     exit_code = exit_code or code
   return exit_code
 
 
 def Execute(arch, mode, args, options, suites, workspace):
@@ skipping 139 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())