Merge revision 6721 to the 3.0 branch.

This fixes a crash triggered when V8 tries to optimize an infinite loop
while the loop is running.

Review URL: http://codereview.chromium.org/6489025

git-svn-id: http://v8.googlecode.com/svn/branches/3.0@6738 ce2b1a6d-e550-0410-aec6-3dcde31c8c00
2 files changed