Add a check to presubmit.py linting python and SCons files for trailing white...

tools/test.py

 #!/usr/bin/env python
 #
 # Copyright 2008 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 372 matching lines @@
       return 0x80000000 & self.output.exit_code and not (0x3FFFFF00 & self.output.exit_code)
     else:
       # Timed out tests will have exit_code -signal.SIGTERM.
       if self.output.timed_out:
         return False
       return self.output.exit_code < 0 and \
              self.output.exit_code != -signal.SIGABRT
 
   def HasTimedOut(self):
     return self.output.timed_out;
-    
+
   def HasFailed(self):
     execution_failed = self.test.DidFail(self.output)
     if self.test.IsNegative():
       return not execution_failed
     else:
       return execution_failed
 
 
 def KillProcessWithID(pid):
   if utils.IsWindows():
@@ skipping 927 matching lines @@
     for entry in timed_tests[:20]:
       t = FormatTime(entry.duration)
       sys.stderr.write("%4i (%s) %s\n" % (index, t, entry.GetLabel()))
       index += 1
 
   return result
 
 
 if __name__ == '__main__':
   sys.exit(Main())