Integer-related fixes for term.c etc.

Integer-related fixes for term.c etc.

* dispextern.h (face_tty_specified_color): New function.
* term.c (turn_on_face): Don't rely on undefined behavior when
assigning an out-of-range value to 'long'.  Simplify
test for toggling highlight.
(tty_capable_p): Omit last two (unused) args.  All callers changed.
* term.c (tty_capable_p, tty_menu_display, tty_menu_add_selection)
(read_menu_input, tty_menu_activate, tty_menu_show):
* xfaces.c (x_supports_face_attributes_p)
(tty_supports_face_attributes_p):
Use bool for boolean.  All callers changed.
(tty_supports_face_attributes_p): Omit defaults for color indices;
no longer needed.  Simplify tail call.