updated for version 7.3.1033

Problem:    "\1" .. "\9" are not supported in the new regexp engine.
Solution:   Implement them.  Add a few more tests.

src/regexp.h

@@ -71,7 +71,6 @@ struct nfa_state
     nfa_state_T		*out1;
     int			id;
     int			lastlist;
-    int			visits;
     int			negated;
 };