A prototype map can't be deprecated.

Bug: v8:7790
Change-Id: I26ef4d9648985417212dcf4df0d47568861e9bc2
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2196124
Auto-Submit: Georg Neis <neis@chromium.org>
Reviewed-by: Michael Stanton <mvstanton@chromium.org>
Commit-Queue: Michael Stanton <mvstanton@chromium.org>
Cr-Commit-Position: refs/heads/master@{#67738}