LargeObjectSpace doesn't make use of filler objects, so if we
create them when right-trimming objects, then that's a waste
of time at best, and causes a segfault in a SLOW_DCHECK at worst,
namely when CreateFillerObjectAt calls GetHeapFromWritableObject
on what's effectively an inner pointer (on some random LO page).

Change-Id: I91bbcaa219db78a0f98660590d5156c4b4a5414e
Reviewed-on: https://chromium-review.googlesource.com/c/v8/v8/+/2972914Reviewed-by: Michael Lippautz <mlippautz@chromium.org>
Commit-Queue: Jakob Kummerow <jkummerow@chromium.org>
Cr-Commit-Position: refs/heads/master@{#75325}