More EBCDIC stuff:

More EBCDIC stuff:
 - Loose the extra level of function on ASCII.
 - spotted a chr(0) issue in sv.c
 - re-work of UTF-X tr/// ranges to work in Unicode
   space. Still issues with the "0xff is illegal UTF-8" hack.
 - Yet another ad. hoc. utf8 'upgrade' in op.c recoded
   (why do it once when you can do it all over the place :-(
 - Enable HINTS_UTF8 on EBCDIC - then ignore it in toke.c,
   need utf8.pm for swashes.
 - Simplified and commented scan_const() in toke.c
Still something wrong regexp and tr (swashes?).

p4raw-id: //depot/perlio@9267