Treat persisted merge queue ownership as an active merge-lane owner when hydrating in-review stall state and when self-healing scans for ghost, stalled, or completion-handoff-limbo tasks.
Also clear false completion-handoff exhaustion for tasks that are still owned by the merge queue so previously poisoned review tasks can continue merging.
Fusion-Task-Id: FN-6086
7a9d2b0f30