R1:f6122547d774

When a lease triggers a resource allocation for a resource which must activate, awaken the lease task after the resource activates

Summary:
Depends on D19753. Ref T13210. This is a small optimization that saves us from waiting up to 15 seconds for a yield.

When there are no Working Copy resources and a new lease comes in, we'll allocate one and yield until it activates.

If activating it (SSH'ing and running `git clone`) takes less than 15 seconds, the resource will activate (say, at T+4) but the lease…