R1:a1baedbd9a08

Lock resources briefly while acquiring leases on them to prevent acquiring near-death resources

Summary:
Depends on D19078. Ref T13073. Currently, there is a narrow window where we can acquire a resource after a reclaim has started against it.

To prevent this, briefly lock resources before acquiring them and make sure they're still good. If a resource isn't good, throw the lease back in the pool.

Test Plan:
This is tricky. You need:

- Hoax blueprint with limits and a rule where leases of a given…