MotionEvent: Rotate relative axes according to window orientation

We rotate the X and Y coordinates of MotionEvents when the window
transform also contains a rotation. This means we should rotate the
relative axes (AXIS_RELATIVE_{X,Y}) as well, making sure not to
translate these relative values.

Bug: 179274888
Test: libinput_tests
Test: manual with test app
Change-Id: I8c716b14ee2b3cd5362f4e9f1554ee37d6875c2d