Support mouse pointer on external displays (1/3)

If input source is mouse, InputTouchMapper and CursorInputMapper will assign
a PointerController which associated with some display.
When dispatch a motion event, it should be assigned the displayId from
PointerController.

- Add getDisplayId for PointerControllerInterface to get the current
  associated display id.
- Add updatePointerDisplay for InputReaderPolicyInterface to find and
  associate the specified display viewport.
- Add test cases for TouchInputMapper and CursorInputMapper.

Bug: 113559891
Test: ActivityView test app
Test: atest inputflinger_tests
Change-Id: Ifc69374a55f39fbc1572d9ea3f979fcbb83b45c0