On very rare circumstances parallel recompilation would install
the optimized method earlier than expected and the test would fail.

BUG=
R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/24495005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@16933 ce2b1a6d-e550-0410-aec6-3dcde31c8c00