Testconfig: Deleting QtWayland specific 12.3 stage

That stage won't work on all nodes anyway, while some of the 12.3
OpenSuSE nodes do not have that wayland libs installed.

Change-Id: I3ca98997d451732cc31597cdd5fcd46c39008769
Reviewed-by: Andrew Knight <andrew.knight@digia.com>
Reviewed-by: Robin Burchell <robin+qt@viroteck.net>