Fix test harness to correctly split extra flags.

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 160 matching lines @@
 
   if options.buildbot:
     # Buildbots run presubmit tests as a separate step.
     options.no_presubmit = True
     options.no_network = True
   if options.command_prefix:
     print("Specifying --command-prefix disables network distribution, "
           "running tests locally.")
     options.no_network = True
   options.command_prefix = shlex.split(options.command_prefix)
+  options.extra_flags = shlex.split(options.extra_flags)
   if options.j == 0:
     options.j = multiprocessing.cpu_count()
   if options.no_stress:
     VARIANT_FLAGS = [[], ["--nocrankshaft"]]
   if not options.shell_dir:
     if options.shell:
       print "Warning: --shell is deprecated, use --shell-dir instead."
       options.shell_dir = os.path.dirname(options.shell)
   if options.stress_only:
     VARIANT_FLAGS = [["--stress-opt", "--always-opt"]]
@@ skipping 171 matching lines @@
   except KeyboardInterrupt:
     return 1
 
   if options.time:
     verbose.PrintTestDurations(suites, overall_duration)
   return exit_code
 
 
 if __name__ == "__main__":
   sys.exit(Main())