Expose WeakMap::Delete on debug interface

Bug: chromium:1213393
Change-Id: I100c5caba38cab3a1ef9511125937ef7b34d818f
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2966381


Reviewed-by: Toon Verwaest <verwaest@chromium.org>
Commit-Queue: Sigurd Schneider <sigurds@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75203}