UNION doesn't return DISTINCT result for multi-byte characters
hp_hash.c:
This piece of code was pretty wrong, looks
like no necessary changes were made after
cut-and-paste from fixed length segment processing.
Itroduced two new variables safe_length1 and
safe_length2 to remember the original lengths.
Fixing my_charpos and set_if_smaller calls
to pass correct parameters.
ctype_utf8.result, ctype_utf8.test:
adding test case
76910cd190