Tune mjsunit/regress/regress-2612.

Lower the bounds to something bearable which would still timeout if we
used a quadratic algorithm.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/39863003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@17377 ce2b1a6d-e550-0410-aec6-3dcde31c8c00