frameworks/base: Watchdog to generate trace of Monkey

We need stacktrace of Monkey process to debug issues wherein
system_server gets stuck doing a binder call with monkey

Change-Id: Ie0be15662c68219fe5e95592c672b86ab0987e37
(cherry picked from commit c509d1147e321118f1c908502b0b9eb5ee2a5926)

Conflicts:
	services/java/com/android/server/Watchdog.java