The problem was that MySQL hadn't true ctype implementation. As a
result many multibyte punctuation/whitespace characters were
treated as word characters.

This fix uses recently added CTYPE table for unicode character sets
(WL1386) to detect unicode punctuation/whitespace characters
correctly.

Note: this is incompatible change since it changes parser behavior.
One will have to use REPAIR TABLE statement to rebuild fulltext
indexes.


mysql-test/r/fulltext2.result:
  Testcase for BUG#19580.
mysql-test/t/fulltext2.test:
  Testcase for BUG#19580.
storage/myisam/ft_parser.c:
  Use WL1386 "CTYPE table for unicode character sets" functionality.
storage/myisam/ft_update.c:
  Use WL1386 "CTYPE table for unicode character sets" functionality.
  
  Reverse fix for BUG#16489 "utf8 + fulltext leads to corrupt index
  file.". It is not needed anymore, since we have true ctype
  implementation.
storage/myisam/ftdefs.h:
  Use WL1386 "CTYPE table for unicode character sets" functionality.
  
  Rework true_word_char macro so it accepts ctype instead of charset
  as first param. It doesn't use my_isalnum anymore, but instead
  directly checks ctype.
  Obsolete word_char macro removed.