The function intended to check the map pointer of an AllocationSiteInfo object, but neglected to
subtract an offset to do so.

BUG=169928

Review URL: https://codereview.chromium.org/11931037

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13444 ce2b1a6d-e550-0410-aec6-3dcde31c8c00