It was a bad idea not to check the count of numbers to add.

Also fix a rollover: the comment in platform-linux.

Review URL: http://codereview.chromium.org/2418001

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@4754 ce2b1a6d-e550-0410-aec6-3dcde31c8c00