Fix hole handling, and ensure smi representation is handled properly

R=jkummerow@chromium.org

Review URL: https://chromiumcodereview.appspot.com/16013003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@14807 ce2b1a6d-e550-0410-aec6-3dcde31c8c00