continue to investigate. For now, use NaN instead of computing
it ourselves.

TBR=sgjesse@chromium.org
Review URL: http://codereview.chromium.org/160267

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2552 ce2b1a6d-e550-0410-aec6-3dcde31c8c00