This is a partial revert of "Make 'tis620-2533' character set be an
alias for 'thai-iso8859-11'" commit from Jul 28, 2018.
* lisp/international/mule-conf.el (tis620-2533): No longer an
alias for thai-iso8859-11. Instead, reinstate the original
definition of tis620-2533, but without eight-bit-control in
the :superset attribute. For the details, see
http://lists.gnu.org/archive/html/emacs-devel/2018-08/msg00117.html
and the surrounding discussions.
* lisp/international/fontset.el (font-encoding-alist)
(font-encoding-charset-alist): Reinstate tis620-2533 charset.
* lisp/language/thai.el (thai-tis620): Restore the original
:charset-list.
("Thai"): Restore the original nonascii-translation.
* lisp/w32-fns.el: Use tis620-2533 instead of thai-iso8859-11.