Remove flag track-allocation-sites.

The flag has been on in the build for ~9 months, and we aren't likely to turn it off. The only customer of the flag is a set of tests that want to verify transitioning behavior in isolation. This CL removes the flag and updates those tests to get what they want without the flag.

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/104923010

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@18385 ce2b1a6d-e550-0410-aec6-3dcde31c8c00