Port r13775 (1fd19d83)

Original commit message:
Allow transitioning from KNOWN_OBJECT to KNONW_OBJECT or OBJECT.
Also, rename HEAP_NUMBER IC states to NUMBER, since they handle Smis, too.

BUG=

Review URL: https://codereview.chromium.org/12387076

git-svn-id: http://v8.googlecode.com/svn/branches/bleeding_edge@13805 ce2b1a6d-e550-0410-aec6-3dcde31c8c00