4077. [test] Add static-stub regression test for DS NXDOMAIN

return making the static stub disappear. [RT #38564]

(cherry picked from commit be9720ae2c)

bin/tests/system/staticstub/ns3/named.conf.in

@@ -57,3 +57,8 @@ zone "example.org" {
 	type master;
 	file "example.org.db";
 };
+
+zone "undelegated" {
+	type master;
+	file "undelegated.db.signed";
+};