Add predictable mode to test driver.

tools/testrunner/objects/output.py

 # 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
 #       copyright notice, this list of conditions and the following
 #       disclaimer in the documentation and/or other materials provided
@@ skipping 20 matching lines @@
 from ..local import utils
 
 class Output(object):
 
   def __init__(self, exit_code, timed_out, stdout, stderr):
     self.exit_code = exit_code
     self.timed_out = timed_out
     self.stdout = stdout
     self.stderr = stderr
 
+  def __ne__(self, other):
+    return (self.exit_code != other.exit_code or
+            self.timed_out != other.timed_out or
+            self.stdout != other.stdout or
+            self.stderr != other.stderr)
+
   def HasCrashed(self):
     if utils.IsWindows():
       return 0x80000000 & self.exit_code and not (0x3FFFFF00 & self.exit_code)
     else:
       # Timed out tests will have exit_code -signal.SIGTERM.
       if self.timed_out:
         return False
       return (self.exit_code < 0 and
               self.exit_code != -signal.SIGABRT)
 
   def HasTimedOut(self):
     return self.timed_out
 
   def Pack(self):
     return [self.exit_code, self.timed_out, self.stdout, self.stderr]
 
   @staticmethod
   def Unpack(packed):
     # For the order of the fields, refer to Pack() above.
     return Output(packed[0], packed[1], packed[2], packed[3])