Refactor processing of relative pointer movements

Refactor to extract common code that controls cursor movement of a
relative mouse in processing of motion events in PointerChoreographer.

Bug: 367660694
Test: atest inputflinger_tests
Flag: EXEMPT refactor
Change-Id: I7f8683f7cda7de6c7bcaf82ceb02dc54b70c71ee
2 files changed