server/grab: add test for proper grab passing
server/grab: add test for proper grab passing

A client rejecting an already-finished grab should pass the touch on to the
next client. That client needs to get the touch end event as well as the
replayed Begin/End events.

Signed-off-by: Peter Hutterer <b9c50af7afa7642f6f854434cda9ffe54ece8b85@who-t.net>

freedesktop-unofficial-mirror/xorg__test__xorg-integration-tests,freedesktop-unofficial-mirror/xorg__test__xorg-integration-tests,freedesktop-unofficial-mirror/xorg__test__xorg-integration-tests