I was comparing the work being done by fd and find and noticed (with
`strace -f -c -S` calls) that fd was doing a ton of failed `statx`
calls. Upon closer inspection it was stating `.jj` even though I
was passing `--no-ignore`. Eventually I turned up this check in
`Ignore::add_child_path` that was doing stat on `.jj` regardless of
whether the options request it.
With this patch it'll only stat `.jj` if that's relevant to the query.
PR #3212
85edf4c796