We do not use rdtsc anywhere and we won't ever use that in the
future, as it is totally unusable with multicore and out of
order execution.

R=jkummerow@chromium.org

Review URL: https://codereview.chromium.org/23112016

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16268 ce2b1a6d-e550-0410-aec6-3dcde31c8c00