Allow setting debugger breakpoints on CompareNilICs

BUG=v8:2660
R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/14106011

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14487 ce2b1a6d-e550-0410-aec6-3dcde31c8c00