xwayland: Destroy the warp emulator on leave

The pointer may leave a surface with a warp emulator active without any
pointer motion event, just by mapping/unmapping or restacking windows.

Destroy the warp emulator when the pointer leaves the surface, not just
on motion events.

Signed-off-by: Olivier Fourdan <ofourdan@redhat.com>
xorg/xserver#1087
4 jobs for issue1087 in 13 minutes and 59 seconds (queued for 3 seconds)
latest
Status Name Job ID Coverage
  Docker Image
passed debian-testing #5112189

00:00:10

 
  Build And Test
passed autotools #5112191

00:13:49

passed meson #5112193

00:01:13

passed meson-noglamor #5112195

00:00:56