Fixed the caching of counters. This also fixes the --dump-counters which reads the counters from the cache when dumping.
Review URL: http://codereview.chromium.org/13171

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@923 ce2b1a6d-e550-0410-aec6-3dcde31c8c00