DO NOT MERGE: Revert "Remove StuckServer using backlog and tests relying on it"
This reverts commit 8ffb0f55.
(DO NOT MERGE because the original CL was a cherry-pick form N,
where this wasn't a problem. It breaks trees only on M.)
Bug: 35934294
(cherry picked from commit d7f172d0)
Change-Id: Id0b18389de73110f3f07f591f4272dbb50b4417b