Merge changes Iacaa796f,I7549f674,Ic9d70880,I96cb09b7,I5c2658a8

* changes:
  crash_dump: set a watchdog timer.
  crash_dump: switch to PTRACE_SEIZE.
  crash_dump: clear the default crash handlers.
  crash_dump: remove extra log.
  debuggerd_handler: actually wait for pseudothread to exit.