If the object to be trimmed creates a filler object that is located just
before the current LAB, then we can immediately give back the memory.

Bug: v8:11872, v8:11883
Change-Id: I9ec37443482334003b3752a3f25fc5dcb6a476fc
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2996643Reviewed-by: Dominik Inführ <dinfuehr@chromium.org>
Commit-Queue: Victor Gomes <victorgomes@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75475}