[roll] Roll fuchsia [fxfs] Fix initial reap to not tombstone an attr after object.

Previously we were silently doing nothing when trying to tombstone an
attribute that didn't exist because it got removed while tombstoning the
object. Now we avoid doing that during initial reap, and the graveyard
entry gets cleaned up during the object tombstone as well. If the
initial reap had ever failed after tombstoning the object but didn't do
the attribute then it would fail FSCK due to the graveyard entry for an
attribute that doesn't exist.

This only addresses the initial reap situation, where it arises that
they get purged in such an order. If someone queued the tombstone for
the object and then the attribute it would break, but that should be a
bad sequence anyways. A follow-up will be adding debug_asserts to
directly address when tombstoning an attribute or object that doesn't
exist.

Original-Original-Bug: 355246066
Original-Original-Reviewed-on: https://fuchsia-review.googlesource.com/c/fuchsia/+/1605448
Original-Original-Revision: 779c7a154a28c4335e940390922a0740f93c79ea
GitOrigin-RevId: de00b46e129cbbff4b77749dfbbff4e2b06e9a00
Change-Id: I958d4e3ee298d206320af72ae364fa3e3b44f165
Reviewed-on: https://fuchsia-review.googlesource.com/c/integration/+/1611028
Cr-Commit-Position: refs/heads/main@{#192582}