wayland: Fix setting geometry hints

The stable xdg_shell port (5c8bb51a) introduced an error in
gdk_wayland_window_set_geometry_hints which would set the minimum size
to the maximum size, if provided.

This resulted in various wxWidgets apps (FileZilla, Audacity, Veracrypt)
crashing because they attempted to allocate a ginormous surface.

Fixes #157.
1 job for gtk-3-22 in 12 minutes and 24 seconds (queued for 3 seconds)
Status Job ID Name Coverage
passed #21282