win32: rollback change and use _gdk_display

This makes usage of _gdk_display again when creating a window.
This is needed because there is a window created when the display
is being initialized, so it becomes a chicken and egg problem.
For now we roll back this to fix the wintab crash but we might
want to fix this again in the future by improving the wintab
initialization.

https://bugzilla.gnome.org/show_bug.cgi?id=764664

gdk/win32/gdkwindow-win32.c

@@ -643,7 +643,7 @@ _gdk_win32_display_create_window_impl (GdkDisplay    *display,
   /* check consistency of redundant information */
   guint remaining_mask = attributes_mask;
 
-  g_return_if_fail (display == gdk_display_get_default ());
+  g_return_if_fail (display == _gdk_display);
 
   GDK_NOTE (MISC,
 	    g_print ("_gdk_window_impl_new: %s %s\n",