keep any address records included in the response to an NS query

Fixes #1671

.gitignore

@@ -23,4 +23,5 @@ rls/**
 
 # ignore fuzzing corpus
 fuzz/artifacts/**
-fuzz/corpus/**
+fuzz/corpus/**
+*~

crates/resolver/src/caching_client.rs

@@ -403,6 +403,8 @@ where
                         {
                             found_name = true;
                             Some((r, ttl))
+                        } else if query.query_type().is_ns() && r.rr_type().is_ip_addr() {
+                            Some((r, ttl))
                         } else {
                             None
                         }