GtkMenu: Try using gdk_window_move_to_rect() more often

GtkMenu: Try using gdk_window_move_to_rect() more often

With best-effort, try to use gdk_window_move_to_rect() more often, when
all pieces fit together. For the non-legacy paths to be triggered for
when gtk_menu_popup_for_device() or gtk_menu_popup() were used, the
following conditions must be met:

 1) There is no custom positioning function specified
 2) The menu is attached to a widget (using gtk_menu_attach_to_widget())
 3) There is a associated grab device

https://bugzilla.gnome.org/show_bug.cgi?id=772922