(note_mouse_highlight): Do nothing if gc_in_progress.

(note_mouse_highlight): Do nothing if gc_in_progress.
Set mouse_face_deferred_gc when that case arise.
(XTframe_up_to_date): If mouse_face_deferred_gc, redo highlighting.

(show_mouse_face): Turn off cursor only if it's
in the area being manipulated.
(XTupdate_begin): Don't turn off highlight if we aren't updating
the window that it is in.