This instruction only depends on the prototype and the holder and can
completely ignore the receiver and its map.

This change also fixes a small bug on arm where a cell was loaded
instead of the prototype from new space.

Review URL: http://codereview.chromium.org/6094020

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@6290 ce2b1a6d-e550-0410-aec6-3dcde31c8c00