Be more explicit about when to flush moves
Be more explicit about when to flush moves

Also makes the non-doublebuffered case work better by flushing before we
call _gdk_windowing_window_process_updates_recurse.

zsx/gtk,alexlarsson/gtk,Distrotech/gtk2,grubersjoe/adwaita,davidgumberg/gtk,jadahl/gtk,jadahl/gtk,johne53/MB3Gtk-2,msteinert/gtk,jigpu/gtk,alexlarsson/gtk,simokivimaki/gtk,zsx/gtk,chipx86/gtk,chipx86/gtk,chergert/gtk,Lyude/gtk-,jadahl/gtk,chergert/gtk,Distrotech/gtk,Sidnioulz/SandboxGtk,alexlarsson/gtk,ebassi/gtk,johne53/MB3Gtk-2,Distrotech/gtk,Unity-Technologies/gtk,davidgumberg/gtk,Lyude/gtk-,chergert/gtk,davidt/gtk,Distrotech/gtk,Distrotech/gtk2,ahodesuka/gtk,chergert/gtk,ahodesuka/gtk,jessevdk/gtk,davidgumberg/gtk,Lyude/gtk-,grubersjoe/adwaita,Adamovskiy/gtk,davidgumberg/gtk,ebassi/gtk,jessevdk/gtk,Adamovskiy/gtk,grubersjoe/adwaita,ebassi/gtk,Distrotech/gtk2,alexlarsson/gtk,nacho/gtk-,Distrotech/gtk2,msteinert/gtk,chergert/gtk,Lyude/gtk-,jadahl/gtk,Distrotech/gtk2,bratsche/gtk-,Unity-Technologies/gtk,simokivimaki/gtk,jigpu/gtk,davidgumberg/gtk,Lyude/gtk-,msteinert/gtk,bratsche/gtk-,msteinert/gtk,bratsche/gtk-,zsx/gtk,jadahl/gtk,Adamovskiy/gtk,davidt/gtk,jigpu/gtk,Unity-Technologies/gtk,Unity-Technologies/gtk,simokivimaki/gtk,Adamovskiy/gtk,davidt/gtk,zsx/gtk,Adamovskiy/gtk,alexlarsson/gtk,simokivimaki/gtk,bratsche/gtk-,Sidnioulz/SandboxGtk,zsx/gtk,nacho/gtk-,ebassi/gtk,Adamovskiy/gtk,jessevdk/gtk,Distrotech/gtk,johne53/MB3Gtk-2,jadahl/gtk,davidt/gtk,jessevdk/gtk,davidgumberg/gtk,ebassi/gtk,jadahl/gtk,chipx86/gtk,jessevdk/gtk,Unity-Technologies/gtk,chergert/gtk,grubersjoe/adwaita,jigpu/gtk,msteinert/gtk,ahodesuka/gtk,Adamovskiy/gtk,jessevdk/gtk,davidt/gtk,ahodesuka/gtk,ahodesuka/gtk,Lyude/gtk-,alexlarsson/gtk,simokivimaki/gtk,jigpu/gtk,Lyude/gtk-,Adamovskiy/gtk,jigpu/gtk,simokivimaki/gtk,jigpu/gtk,bratsche/gtk-,davidgumberg/gtk,nacho/gtk-,davidt/gtk,Sidnioulz/SandboxGtk,davidgumberg/gtk,Distrotech/gtk,alexlarsson/gtk,ahodesuka/gtk,nacho/gtk-,jessevdk/gtk,chipx86/gtk,Sidnioulz/SandboxGtk,johne53/MB3Gtk-2,chergert/gtk,Sidnioulz/SandboxGtk,Sidnioulz/SandboxGtk,ahodesuka/gtk,johne53/MB3Gtk-2,jigpu/gtk,grubersjoe/adwaita,bratsche/gtk-,Lyude/gtk-,msteinert/gtk,grubersjoe/adwaita,grubersjoe/adwaita,alexlarsson/gtk,ebassi/gtk,chergert/gtk,grubersjoe/adwaita,ahodesuka/gtk,jadahl/gtk,chipx86/gtk,Distrotech/gtk2,nacho/gtk-