Some QtDeclarative libraries are not binary reproducible

Hi,

The following libraries appear to be unreproducible in binary form depending on the number of threads used for compilation:
 - libQt6QuickControls2FluentWinUI3StyleImpl.so.6.8.2
 - libQt6QuickDialogs2QuickImpl.so.6.8.2
since the generated sources are not identical:
 - libQt6QuickControls2FluentWinUI3StyleImpl.so.6.8.2 (in src/quickcontrols/fluentwinui3/.rcc/qmlcache/):
    - QuickControls2FluentWinUI3StyleImpl_ButtonBackground_qml.cpp
    - QuickControls2FluentWinUI3StyleImpl_CheckIndicator_qml.cpp
    - QuickControls2FluentWinUI3StyleImpl_RadioIndicator_qml.cpp
 - libQt6QuickDialogs2QuickImpl.so.6.8.2 (in src/quickdialogs/quickdialogsquickimpl/.rcc/qmlcache/QuickDialogs2QuickImpl_qml/{.,+Fusion,+Imagine,+Material,+Universal})
    - FileDialog_qml.cpp
    - FolderDialog_qml.cpp
Different host and different number of core used leads to different binaries however, I have attached an example.