Skip regress-crbug-137689.js when running with GC stress

It depends on maps not disappearing prematurely.

R=verwaest@chromium.org

Review URL: https://codereview.chromium.org/720853002

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@25302 ce2b1a6d-e550-0410-aec6-3dcde31c8c00