When deleting a JSObject's last property, only that particular slot
in the old-to-new rememebered set needs to be deleted. The object's
slots don't need to be invalidated anymore since V8 doesn't use
unboxed doubles anymore. While the runtime could install another
property at this address, it will therefore always be a tagged pointer.

Bug: v8:12578, chromium:1316289
Change-Id: Ief072f58e53501c1c1f01c902e21467a37ccdc3c
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/3620274
Commit-Queue: Dominik Inführ <dinfuehr@chromium.org>
Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Reviewed-by: Camillo Bruni <cbruni@chromium.org>
Cr-Commit-Position: refs/heads/main@{#80303}