Should be num_locals, and const.

R=titzer@chromium.org

Bug: v8:8562
Change-Id: I60889c9912ef95d344ede4d7755028116feee47e
Reviewed-on: https://chromium-review.googlesource.com/c/1373784Reviewed-by: Ben Titzer <titzer@chromium.org>
Commit-Queue: Clemens Hammacher <clemensh@chromium.org>
Cr-Commit-Position: refs/heads/master@{#58197}