Testing priority donation.
If the statements printed below are all true, you pass.
1. This thread should have priority 30.  Actual priority: 30.
2. This thread should have priority 31.  Actual priority: 31.
3. acquire2: got the lock
4. acquire2: done
5. acquire1: got the lock
6. acquire1: done
7. acquire2, acquire1 must already have finished, in that order.
8. This should be the last line before finishing this test.
Priority donation test done.