init: init_kill_services_test

Kill processes and make sure the phone recovers. This adds a basic level
of testing, but it could be improved by:
- trying to kill all running processes on the device
- improving metrics for 'recovery'

Bug: 148236233
Test: init_kill_services_test
Change-Id: I8aaca7bf4bb0be588decf741d1f6e1c5787cea84