For some scalings, setClipRect(QRect) would produce a clip one pixel
different from setClipRect(QRectF) because of different
rounding. Ditto for setClipRegion. Fix by making sure to transform
QRectFs instead of QRects.
Fixes: QTBUG-78962
Fixes: QTBUG-78963
Change-Id: I0be721133858c30769ec6d81e978962a3d6b70cf
Reviewed-by: Christoph Cullmann <cullmann@kde.org>
Reviewed-by: Allan Sandfeld Jensen <allan.jensen@qt.io>