Gdk/Win32: Fix resizing surfaces

Gdk/Win32: Fix resizing surfaces

This attempts to fix the counter-intuitive resizing of surfaces in GTK4 where
the surface grows or shrinks at the right and/or bottom edge when the window
resized from the top and/or left edge(s).

This is not yet perfect as the window stutters upon resizing from the top
and/or left edges, but at least makes resizing more intuitive.