Remove temporarily the reference returned by QTransform::toAffine()
since we don't keep the QMatrix object internally anymore.
This is done in order to compile the rest of the code.
The follow-up patch is going to remove that method completely.
Task-number: QTBUG-81628
Change-Id: If7140eedb7582d81ac8da529017cf792174e86ab
Reviewed-by: Lars Knoll <lars.knoll@qt.io>