control/controlclient: use dnscache.Resolver for Noise client

This passes the *dnscache.Resolver down from the Direct client into the
Noise client and from there into the controlhttp client. This retains
the Resolver so that it can share state across calls instead of creating
a new resolver.

Updates #4845
Updates #6110

Signed-off-by: Andrew Dunham <andrew@du.nham.ca>
Change-Id: Ia5d6af1870f3b5b5d7dd5685d775dcf300aec7af

control/controlclient/noise_test.go

@@ -74,7 +74,12 @@ func (tt noiseClientTest) run(t *testing.T) {
 	defer hs.Close()
 
 	dialer := new(tsdial.Dialer)
-	nc, err := NewNoiseClient(clientPrivate, serverPrivate.Public(), hs.URL, dialer, nil, nil, nil)
+	nc, err := NewNoiseClient(NoiseOpts{
+		PrivKey:      clientPrivate,
+		ServerPubKey: serverPrivate.Public(),
+		ServerURL:    hs.URL,
+		Dialer:       dialer,
+	})
 	if err != nil {
 		t.Fatal(err)
 	}