Remove invalid HCheckValue case in check elimination.
Remove invalid HCheckValue case in check elimination.

Also eliminate a useless copy of the map set in case of
HCheckMaps.

R=svenpanne@chromium.org

Review URL: https://codereview.chromium.org/256593011

git-svn-id: b158db1e4b4ab85d4c9e510fdef4b1e8c614b15b@21033 ce2b1a6d-e550-0410-aec6-3dcde31c8c00

UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh,UniversalFuture/moosh