scrolled window: Fix size requisition with overlay scrolling
scrolled window: Fix size requisition with overlay scrolling

When the scrollbars are overlayed, the size requisition of the
scrolled window should not depend on whether the scrollbars are
visible or not. This was not quite the case, because we forgot
one case where scrollbar size was still added to the requisition.

alexlarsson/gtk,davidgumberg/gtk,alexlarsson/gtk,chergert/gtk,grubersjoe/adwaita,Adamovskiy/gtk,jigpu/gtk,chergert/gtk,chergert/gtk,jigpu/gtk,davidgumberg/gtk,jadahl/gtk,jigpu/gtk,jadahl/gtk,ahodesuka/gtk,grubersjoe/adwaita,chergert/gtk,davidgumberg/gtk,chergert/gtk,grubersjoe/adwaita,jigpu/gtk,ahodesuka/gtk,Adamovskiy/gtk,chergert/gtk,grubersjoe/adwaita,alexlarsson/gtk,alexlarsson/gtk,jigpu/gtk,chergert/gtk,Lyude/gtk-,ahodesuka/gtk,grubersjoe/adwaita,ahodesuka/gtk,davidgumberg/gtk,ahodesuka/gtk,grubersjoe/adwaita,davidgumberg/gtk,jigpu/gtk,ahodesuka/gtk,Adamovskiy/gtk,Lyude/gtk-,jigpu/gtk,Adamovskiy/gtk,alexlarsson/gtk,chergert/gtk,grubersjoe/adwaita,Adamovskiy/gtk,jadahl/gtk,jadahl/gtk,alexlarsson/gtk,davidgumberg/gtk,Adamovskiy/gtk,Lyude/gtk-,alexlarsson/gtk,grubersjoe/adwaita,ahodesuka/gtk,Lyude/gtk-,Adamovskiy/gtk,Adamovskiy/gtk,Lyude/gtk-,davidgumberg/gtk,Lyude/gtk-,Lyude/gtk-,Lyude/gtk-,jadahl/gtk,ahodesuka/gtk,jigpu/gtk,davidgumberg/gtk,jadahl/gtk,alexlarsson/gtk,jadahl/gtk,jadahl/gtk