Rollback of r13735 in 3.17 branch.

Send SIGPROF signals on the profiler event processor thread

BUG=v8:2364
R=mstarzinger@chromium.org

Review URL: https://codereview.chromium.org/14087016

git-svn-id: https://v8.googlecode.com/svn/branches/3.17@14340 ce2b1a6d-e550-0410-aec6-3dcde31c8c00