[test-runner] Move test case processing beyond the multi-process boundary.

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 585 matching lines @@
   args_suites = OrderedDict() # Used as set
   for arg in args:
     args_suites[arg.split('/')[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(BASE_DIR, "test", root))
     if suite:
+      suite.SetupWorkingDirectory()
       suites.append(suite)
 
   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:
@@ skipping 182 matching lines @@
   if exit_code == 1 and options.json_test_results:
     print("Force exit code 0 after failures. Json test results file generated "
           "with failure information.")
     exit_code = 0
 
   return exit_code
 
 
 if __name__ == "__main__":
   sys.exit(Main())