If there are many shortliving closures, they pollute sampler window and
delay optimizations of functions which should be optimized.

Review URL: http://codereview.chromium.org/6344006

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6364 ce2b1a6d-e550-0410-aec6-3dcde31c8c00