TouchpadInputMapper: rotate multi-finger swipes with display

Or more specifically, rotate the fake fingers for them — the
`GESTURE_{X,Y}_OFFSET` axes are unaffected by the screen rotation.

Bug: 263378323
Test: Rotate device to landscape, check multi-finger swipe pointers are rotated
Test: atest inputflinger_tests
Change-Id: I376588f3574f6cd6ba54b5d84a6da3d76b4159f4
2 files changed