If all uses of a CheckTaggedHole[convert-hole-to-undefined] node
truncate to word32, we can replace the hole check with a Smi check
and return the result as word32.

R=jarin@chromium.org

Review-Url: https://codereview.chromium.org/2079233006
Cr-Commit-Position: refs/heads/master@{#37142}