message: run_tests.py: add "opt" option to be set by default to O2
diff: @@ -1084,7 +1084,7 @@ if __name__ == "__main__":
  parser.add_option("-c", "--compiler", dest="compiler_exe", help="C/C++ compiler binary to use to run tests",
  default=None)
  parser.add_option('-o', '--opt', dest='opt', choices=['', 'O0', 'O1', 'O2'], help='Set optimization level passed to the compiler (O0, O1, O2).',
  - default='')
  + default='O2')
  parser.add_option('-j', '--jobs', dest='num_jobs', help='Maximum number of jobs to run in parallel',
  default="1024", type="int")
  parser.add_option('-v', '--verbose', dest='verbose', help='Enable verbose output',
  