Before this patch, when the profile is locked on Android, we would call "ps",
parse the human-readable output and kill any other Gecko process that we could
find.
But this is completely unnecessary, as we know exactly that the PID of the
process holding the lock is.
In this patch we just kill the process holding the lock since this is
equivalent to the previous behavior.
Differential Revision: https://phabricator.services.mozilla.com/D106186
