The prototype is implicitly checked through a map check of the holder.
This is either checked in CheckPrototypes, or as part of the IC.

Review URL: https://chromiumcodereview.appspot.com/13529017

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@14155 ce2b1a6d-e550-0410-aec6-3dcde31c8c00