Fixed bounds check removal by restricting it to int32 indexes (and reenabled both ABCR and index dehoisting).

BUG=
TEST=

Review URL: https://chromiumcodereview.appspot.com/10905232

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@12493 ce2b1a6d-e550-0410-aec6-3dcde31c8c00