There's no reason to have JavaScript wrappers for those accessors,
since the meat is already in hand-written native code (via %_DateField).
First step now to put them into native builtins. Next step will be to
completely remove %_DateField.

R=yangguo@chromium.org

Review URL: https://codereview.chromium.org/1567353002

Cr-Commit-Position: refs/heads/master@{#33172}