ENG-5569: Cleanup, FaultDistributor is no longer a thing.  Delete it,
all its ilk, and move the one method we still need to LeaderAppointer,
which is currently responsible for partition detection.
ENG-5569: Make @Shutdown less flail-y.
- Prevent crash logs when @Shutdown is requested
- Generate log messages stating what's happening
- Synchronize all sites on a MP boundary to minimize spurious
  higher-level fault detection messages
- Add a failsafe thread to kill nodes after 10 seconds if something
  somehow interrupts the @Shutdown procedures (an unexpected node
  failure during the prepare phase, for example)
- Reduce some logging when it's known we're shutting down
ENG-5569: Add junit test for @Shutdown
ENG-5569: Cleanup, delete pre-existing dead debugging code
Merge pull request #1120 from VoltDB/eng5569

Eng5569