#4451 limited recursion for capture groups in the parser. However, unlimited recursion in the parser is still possible for regexes that use non-capturing groups or lookahead assertions. This PR similarly limits the recursion for such constructs by using the parser's pre-existing internal recursion counter, _Disj_count.

This supersedes the capture group limit introduced by #4451 as a way to prevent stack overflows. But I'm leaving it in because regexes using more than 1000 capture groups strike me as bogus anyway. (I think the error code error_space would be more appropriate in this case now, since the limit is no longer about preventing recursion, but it's probably not worth introducing a minor behavior difference just for this reason. One could even argue that error_space is more appropriate for the new stack limit introduced by this PR, too, because error_space is about regex construction, while error_stack is about regex matching.)

I also fix a mistake in _Matcher2::_Skip()'s recursion limitation: In #5576, I accidentally missed to pass the recursion counter as an argument to one of the recursive calls.