PATCH [perl #121144]: \S, \W, etc fail for above ASCII

There were three things wrong with these couple of lines of code.that
help generate the synthetic start class (SSC).

1)  It used PL_regkind, instead of straight OP.  This meant that /u
    matches were treated the same as /d matches since they both have the
    same regkind.
2)  For what it thought was just for /d, it used the complement of
    ASCII, which matches 128-INFINITY, whereas it wanted 128-255 only..
3)  It did a union of this complement, instead of a subtract of the
    non-complement, forgetting that we are about to complement the
    result, so that if we want the end result to have something, we
    better have the input not have that something, or the complementing
    will screw it up.