Simplify by using FOR_EACH_FRAME here and there.

Simplify by using FOR_EACH_FRAME here and there.
* frame.c (next_frame, prev_frame, other_visible_frames)
(delete_frame, visible-frame-list): Use FOR_EACH_FRAME.
* w32term.c (x_window_to_scroll_bar): Likewise.
* window.c (window_list): Likewise.
* xdisp.c (x_consider_frame_title): Likewise.
* xfaces.c ( Fdisplay_supports_face_attributes_p): Likewise.
* xfns.c (x_window_to_frame, x_any_window_to_frame)
(x_menubar_window_to_frame, x_top_window_to_frame): Likewise.
* xmenu.c (menubar_id_to_frame): Likewise.
* xselect.c (frame_for_x_selection): Likewise.
* xterm.c (x_frame_of_widget, x_window_to_scroll_bar)
(x_window_to_menu_bar): Likewise.
* w32fns.c (x_window_to_frame): Likewise.  Adjust comment.