Increase timeout when running test.py with the --stress-opt option.

Review URL: https://chromiumcodereview.appspot.com/9361033

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@10650 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

tools/test.py

@@ -711,7 +711,7 @@ class Context(object):
   def GetTimeout(self, testcase, mode):
     result = self.timeout * TIMEOUT_SCALEFACTOR[mode]
     if '--stress-opt' in self.GetVmFlags(testcase, mode):
-      return result * 2
+      return result * 4
     else:
       return result