Change the updating of the counters for global stub use to be consistent. Now counters are updated when they are sure to count to avoid decrementing them when there is a miss.
Review URL: http://codereview.chromium.org/160265

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@2554 ce2b1a6d-e550-0410-aec6-3dcde31c8c00