Don't treat warnings as errors when compiling minfrog items.

tools/testing/perf_testing/create_graph.py

 #!/usr/bin/python
 
 # Copyright (c) 2011, the Dart project authors.  Please see the AUTHORS file
 # for details. All rights reserved. Use of this source code is governed by a
 # BSD-style license that can be found in the LICENSE file.
 
 import datetime
 import math
 try:
   from matplotlib.font_manager import FontProperties
@@ skipping 588 matching lines @@
     self.trace_file = os.path.join('..', 'tools', 'testing', 'perf_testing', 
         self.result_folder_name, self.result_folder_name + self.cur_time)
     
     self.AddSvnRevisionToTrace(self.trace_file)    
 
     elapsed = TimeCmd([os.path.join('.', 'frog.py'), '--',
         '--out=minfrog', 'minfrog.dart'])
     RunCmd(['echo', '%f Compiling on Dart VM in production mode in seconds' 
         % elapsed], self.trace_file, append=True)
     elapsed = TimeCmd([os.path.join('.', 'minfrog'), '--out=minfrog',
-        '--warnings_as_errors', 'minfrog.dart', os.path.join('tests', 
-        'hello.dart')])
+        'minfrog.dart', os.path.join('tests', 'hello.dart')])
     if elapsed < self.failure_threshold['Bootstrapping']:
       #minfrog didn't compile correctly. Stop testing now, because subsequent
       #numbers will be meaningless.
       return
     size = os.path.getsize('minfrog')
     RunCmd(['echo', '%f Bootstrapping time in seconds in production mode' % 
         elapsed], self.trace_file, append=True)
     RunCmd(['echo', '%d Generated checked minfrog size' % size],
         self.trace_file, append=True)
 
@@ skipping 130 matching lines @@
       if HasNewCode():
         RunTestSequence(cl, size, language, perf)
       else:
         time.sleep(SLEEP_TIME)
   else:
     RunTestSequence(cl, size, language, perf)
 
 if __name__ == '__main__':
   main()