cssnode: Change the way we invalidate timestamps
cssnode: Change the way we invalidate timestamps

Do not propagate the TIMESTAMP change through the node tree, as that
causes lots of uneeded markings of nodes as invalid.

Instead, walk the node tree and find the nodes that have a non-static
style and only invalidate timestamps on those.

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