Pass checked values to HLoadNamedField, removing the need for extra type-check field.

R=titzer@chromium.org

Review URL: https://chromiumcodereview.appspot.com/22831003

git-svn-id: https://v8.googlecode.com/svn/branches/bleeding_edge@16260 ce2b1a6d-e550-0410-aec6-3dcde31c8c00