Also, remove CSA (slow) asserts of "IsMap(map)" where possible.

Bug: v8:6949, v8:11074
Change-Id: I99c1ede426681a4ec8e7d8a3cc0138557850e164
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2521155Reviewed-by: Dan Elphick <delphick@chromium.org>
Commit-Queue: Santiago Aboy Solanes <solanes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#71013}