Add additional lanes if current jobs will run too long.

With the incoming long-running job feature comes the possibility that
all usable slots are occupied for long periods of time (eg. for hours),
so if we detect that other jobs would be stuck waiting in the queue for
too long then we'll create at most 2 extra slots (one for EJs, one for
regular jobs) so that we can make forward progress with the other jobs.

Bug: 248386641
Test: atest frameworks/base/services/tests/mockingservicestests/src/com/android/server/job
Test: atest frameworks/base/services/tests/servicestests/src/com/android/server/job
Test: atest CtsJobSchedulerTestCases
Change-Id: I7a41a5c8371714a0285bb2dcfe115c762c0d8ed7