[user-timing] Removed vendor prefixes in user timing tests (#339)

Fixing error reported by James at
 http://lists.w3.org/Archives/Public/public-web-perf/2013Sep/0043.html

View on GitHub: https://github.com/w3c/web-platform-tests/pull/339

Received on Tuesday, 17 September 2013 13:26:44 UTC