R1:78ab675bd8aa

After a Drydock lease triggers a resource to be reclaimed, stop it from triggering another reclaim until the first one completes

Summary:
Depends on D19752. Ref T13210. If resources take a long time to reclaim/destroy (normally, more than 15 seconds) a single new lease may update several times during the reclaim/destroy process and end up reclaiming multiple resources.

Instead: after a lease triggers a reclaim, prevent it from triggering another reclaim as long as the resource it is reclaiming hasn't…