Running `ServerKillingChaosMonkey` via `RESTApiClusterManager` for any
duration of time slowly leaks region servers. I see failures on the
RESTApi side go unreported on the ChaosMonkey side. It seems like
`RuntimeException`s are being thrown and lost.
`PolicyBasedChaosMonkey` uses a primitive means of thread management
anyway. Update to use a thread pool, thread groups, and an
uncaughtExceptionHandler.
Signed-off-by: Bharath Vissapragada <bharathv@apache.org>
Signed-off-by: Viraj Jasani <vjasani@apache.org>
89cf76c2cd