adwaita wm: fix right border on left tiled windows.
adwaita wm: fix right border on left tiled windows.

DoctorJellyface/gnome-themes-standard,rgcjonas/adwaita-semidark,DoctorJellyface/gnome-themes-standard,Distrotech/gnome-themes-standard,ChrisCummins/gnome-themes-standard,ChrisCummins/gnome-themes-standard,ChrisCummins/gnome-themes-standard,Distrotech/gnome-themes-standard,ChrisCummins/gnome-themes-standard,rgcjonas/adwaita-semidark,rgcjonas/adwaita-semidark,rgcjonas/adwaita-semidark,ChrisCummins/gnome-themes-standard