[REG: 5.11->6] Performance issue with loading images in static build

Attached example tries to load images and performance has come down quite a lot and seems to only occur in static builds.

Profiling the application points to CBor and parsing of plugin meta data, which takes quite significant amount of time. Especially in Qt 5.15. Situation is a lot better in Qt 6 generally, but it is still much slower there in static builds than in dynamic builds.

Perhaps it shouldn't be doing all this meta data parsing for every call.

Also even though the situation has improved with Qt 6, it still seems to be much worse on Windows than on other platforms.