test: harden scheduling review boundaries

tests/scheduling/test_lifecycle.py

@@ -261,8 +261,6 @@ async def test_settlement_does_not_block_the_event_loop(
         settlement_finished.set()
 
     monkeypatch.setattr(Scheduler, "record_stopped_execution", _blocking_settle)
-    release_timer = threading.Timer(1.0, release.set)
-    release_timer.start()
     try:
         await service.start()
         service.schedule_store.create_schedule(_sched_model("a", intended))
@@ -275,7 +273,6 @@ async def test_settlement_does_not_block_the_event_loop(
         await _wait_for(lambda: service.live_executions == 0)
     finally:
         release.set()
-        release_timer.cancel()
         await service.stop()
 
 
@@ -303,8 +300,6 @@ async def test_shutdown_joins_cancelled_settlement_before_releasing_ownership(
         original(self, run_id, state, now)
 
     monkeypatch.setattr(Scheduler, "record_stopped_execution", _blocking_settle)
-    release_timer = threading.Timer(1.0, release.set)
-    release_timer.start()
     try:
         await service.start()
         service.schedule_store.create_schedule(_sched_model("a", intended))
@@ -328,7 +323,6 @@ async def test_shutdown_joins_cancelled_settlement_before_releasing_ownership(
         ).status.value == ("completed")
     finally:
         release.set()
-        release_timer.cancel()
         await service.stop()