Stricter validation of motion events in dispatcher

We are already validating incoming motion events, but for the events
received from the bottom layers, currently there's no crash.

Add a crash to ensure that the data that the dispatcher is getting is
good. Ideally, this would be done directly in the constructor for
NotifyMotionArgs, but that could be a separate refactor after we convert
pointerProperties and PointerCoords to std::vector.

Bug: 211379801
Test: m inputflinger_tests && $ANDROID_HOST_OUT/nativetest64/inputflinger_tests/inputflinger_tests
Change-Id: Id089db27245827de7c8f83b57dbf38adf820b5f8