Do not crash if InputClassifier HAL crashes

If InputClassifier HAL crashes for some reason, we don't have to crash
the system. Instead, just check return type and move on. The
InputClassifier stage is not critical to input dispatch, and the phone
can remain perfectly functional without this stage.
Log an error message instead.

We are also assuming in InputClassifier that HAL is always present.

There are 2 lines of defense here:
1) MotionClassifier always checks the returns from the HAL. If any of
the returns are not OK, then MotionClassifier thread exits. This is safe
to do always, but a downside of this is that logspam will occur if
events are not able to be added to the queue (since the thread that is
to be consuming them is no longer running).

2) Register HAL death recipient in InputClassifier. When the HAL death
occurs, mMotionClassifier will be set to null, thus
preventing further events from going into the queue. This will avoid the
logspam from 1).

Test: ps -A | grep -i input. Then interact with the phone. Then kill the
HAL process, 'killall
android.hardware.input.classifier@1.0-service-example'. Then make sure
that phone remains functional.
Bug: 117935272

Change-Id: I7e8f676d3baa0703198f0731273678c3575bdf60