Eliminate unnecessary patching of load-length ICs in megamorphic state.
Eliminate unnecessary patching of load-length ICs in megamorphic state.

This avoid the worst case of patching ICs repeatedly with the
same stub code object.

BUG=v8:1489
Review URL: http://codereview.chromium.org/7230007

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@8364 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh