Split ANYOF_NONBITMAP into two components

Split ANYOF_NONBITMAP into two components

ANYOF_NONBITMAP means that the node can match things that aren't in its
bitmap.  Some things can match only when the target string is in utf8,
and some things can match even if it isn't.  If the target string is not
in utf8, and we know that the only possible match is when it is in utf8,
we know it can't match, and avoid a fruitless, expensive swash load.

This change also fixes a number of problems shown in t/re/grind_fold.t
that I will deliver soon.