[regression] Memory and CPU usage accumulation in QWaylandWindow

textureinsgnode (fboitem) example starts to leak/accumulate memory and increase CPU consumption after 2.5h of running and will continue to increase at least 20h into running*.

Before the accumulation starts everything is fine. CPU/RAM consumption both are steady. So the cause is probably an overflow in handle numbers or similar.

Normal running on the board textureinsgnode uses 17/400 of CPU and after 10 hours it is 110/400 . PSS in the same time goes from 30MB to over 300MB.

Issue can be reproduced with both Weston and Simple QML compositor. The issue is not reproduced when running textureinsgnode directly with eglfs backend.

*No multiday tests conducted. 5 hours of running is a good test point for reproduction.