(Fput_char_attribute): Use <Lisp_Object> (integer) instead of list of

(Fput_char_attribute): Use <Lisp_Object> (integer) instead of list of
<Lisp_Object>s (integers) as the format of code-point of a
coded-charset.
(range_charset_code_point): Return <int> instead of <Lisp_Object>.
(encode_builtin_char_1): New function; delete `split_builtin_char'.
(charset_code_point): Return <int> instead of <Lisp_Object>.
(Fsplit_char): Don't use `SPLIT_CHAR'.