Move native crash detection to Package Watchdog

For the sake of consolidating various error detection mechanisms,
move native crash detection to Package Watchdog. Add a method
to allow the traditional threshold logic to be bypassed in this
case. This method will be used in the future for prioritizing
explicit health check failures.

Test: atest StagedRollbackTest#testNativeWatchdogTriggersRollback
Bug: 145584672
Change-Id: I98eb9f45a6f4a6d15001650e31ba9c596905663a