[2377] Check the implementation accepts quoted names

This is questionable if it should be allowed (at least vim marks it in
red as error), but bind9 accepts it, so shall we too.

src/lib/dns/tests/testdata/example.org

@@ -7,7 +7,8 @@ example.org.        3600    IN  SOA ( ; The SOA, split across lines for testing
     2419200
     7200
     )
-example.org.        3600    IN  NS ns1.example.org.
+; Check it accepts quoted name too
+"\101xample.org."        3600    IN  NS ns1.example.org.
 
 
 ; Some empty lines here. They are to make sure the loader can skip them.