Don't use PLY cache files in Tools/Scripts/run-bindings-tests

Source/bindings/scripts/blink_idl_lexer.py

 # Copyright (C) 2013 Google Inc. 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
@@ skipping 92 matching lines @@
             if rewrite_tables:
                 tablefile_root = os.path.join(outputdir, LEXTAB)
                 # Also remove the .pyc/.pyo files, or they'll be used even if
                 # the .py file doesn't exist.
                 for ext in ('.py', '.pyc', '.pyo'):
                     try:
                         os.unlink(tablefile_root + ext)
                     except OSError:
                         pass
 
+            lextab = LEXTAB
+        else:
+            lextab = None
+
         IDLLexer.__init__(self)
         # Overrides to parent class
         self._RemoveTokens(REMOVE_TOKENS)
         # Optimized mode substantially decreases startup time (by disabling
         # error checking), and also allows use of Python's optimized mode.
         # See: Optimized Mode
         # http://www.dabeaz.com/ply/ply.html#ply_nn15
         self._lexobj = lex.lex(object=self,
                                debug=debug,
                                optimize=optimize,
-                               lextab=LEXTAB,
+                               lextab=lextab,
                                outputdir=outputdir)
 
 
 ################################################################################
 
 def main(argv):
     # If file itself executed, build and cache lex table
     try:
         outputdir = argv[1]
     except IndexError as err:
         print 'Usage: %s OUTPUT_DIR' % argv[0]
         return 1
     # Important: rewrite_tables=True causes the cache file to be deleted if it
     # exists, thus making sure that PLY doesn't load it instead of regenerating
     # the parse table.
     lexer = BlinkIDLLexer(outputdir=outputdir, rewrite_tables=True)
 
 
 if __name__ == '__main__':
     sys.exit(main(sys.argv))