xi: Don't deliver emulated motion when there's no owner for touch end

Pointer-emulated touch events should only be delivered to the client
that owns the sequence even if it's a core client that became the
effective owner of the sequency by selecting for pointer press and
movement.

Currently the emulated events are delivered like this already (see
TouchResourceIsOwner() check in DeliverEmulatedMotionEvent()), except in
the case of TouchEnd, in which case the generated motion event is still
delivered to some client that's not necessarily the owner of the touch
sequence.

We already know whether a touch sequence that is about to emulate a
pointer event has an owner, we just need to check that. This further
allows to simplify DeliverEmulatedMotionEvent() as it won't ever be
called for non-owned touch events.

https://bugs.freedesktop.org/show_bug.cgi?id=60394

Signed-off-by: Povilas Kanapickas <povilas@radix.lt>
4 jobs for fix-extraneous-motion-event-when-no-touch-end-owner in 6 minutes and 58 seconds (queued for 1 second)