Update the lookup and update code for code caches to deal with deleted
elements.

Do not clear the code cache for the builtins object.  If there was a
matching element in the code cache, we would have hit the monomorphic
prototype failure case and removed it.
Review URL: http://codereview.chromium.org/3140

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@340 ce2b1a6d-e550-0410-aec6-3dcde31c8c00