Move Joystick and Touchpad event transformation logic to MotionEvent

We would like to have all source and axis based transformations
calculated in the same place, which will be in the MotionEvent class.
This has the added benefit that MotionEvents created by developers
through MotionEvent.obtain() in Java will behave like motion events
generated from input devices in terms of how they're affected by
transformations.

Since axes from joysticks and touchpads should never be transfomred,
we previously solved this by using identity matrices for them in
InputDispatcher. Now, we move that logic to MotionEvent when applying
the transform.

Bug: 179274888
Test: atest libinput_test
Test: atest inputflinger_tests
Change-Id: Ic02466e01f2ba3131aca73bd10933ff81cb38cc9