Add dual stack DNS lookup test

tests/manual-tests/test-ds-dns-lookup.py

@@ -0,0 +1,13 @@
+import dns.message
+import socket
+
+s = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
+s.bind(('0.0.0.0', 0))
+
+s.sendto(dns.message.make_query('example.org', 'A').to_wire(), ('8.8.8.8', 53))
+s.sendto(dns.message.make_query('example.org', 'AAAA').to_wire(), ('8.8.8.8', 53))
+
+data, _ = s.recvfrom(0xffff)
+print(dns.message.from_wire(data))
+data, _ = s.recvfrom(0xffff)
+print(dns.message.from_wire(data))