crashes uncovered by this were caused by constant pool in safe-point
tables. This should be safe to enable now.

Review URL: http://codereview.chromium.org/6243005

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6348 ce2b1a6d-e550-0410-aec6-3dcde31c8c00