drill

f8e5e613 - DRILL-2697: Pauses sites wait indefinitely for a resume signal DrillClient sends a resume signal to UserServer. UserServer triggers a resume call in the correct Foreman. Foreman resumes all pauses related to the query through the Control layer.

DRILL-2697: Pauses sites wait indefinitely for a resume signal DrillClient sends a resume signal to UserServer. UserServer triggers a resume call in the correct Foreman. Foreman resumes all pauses related to the query through the Control layer. + Better error messages and more tests in TestDrillbitResilience and TestPauseInjection + Added execution controls to operator context + Removed ControlMessageHandler interface, renamed ControlHandlerImpl to ControlMessageHandler + Added CountDownLatchInjection, useful in cases like ParititionedSender that spawns multiple threads