Multiple resolvers in the "wildcard" system test are configured with a
single root hint: "ns.root-servers.nil", pointing to 10.53.0.1, which is
inconsistent with authoritative data served by ns1.  This may cause
intermittent resolution failures, triggering false positives for the
"wildcard" system test.  Prevent this from happening by making ns2, ns3,
and ns5 use root hints corresponding to the contents of ns1/root.db.in.

(cherry picked from commit dd430c30)