Fix the resolvers RTT-ranged responses statistics counters

When a response times out the fctx_cancelquery() function
incorrectly calculates it in the 'dns_resstatscounter_queryrtt5'
counter (i.e. >=1600 ms). To avoid this, the rctx_timedout()
function should make sure that 'rctx->finish' is NULL. And in order
to adjust the RTT values for the timed out server, 'rctx->no_response'
should be true. Update the rctx_timedout() function to make those
changes.

lib/dns/resolver.c

@@ -8049,6 +8049,9 @@ rctx_timedout(respctx_t *rctx) {
 		fctx->timeout = true;
 		fctx->timeouts++;
 
+		rctx->no_response = true;
+		rctx->finish = NULL;
+
 		now = isc_time_now();
 		/* netmgr timeouts are accurate to the millisecond */
 		if (isc_time_microdiff(&fctx->expires, &now) < US_PER_MS) {
@@ -8059,8 +8062,6 @@ rctx_timedout(respctx_t *rctx) {
 		} else {
 			FCTXTRACE("query timed out; trying next server");
 			/* try next server */
-			rctx->no_response = true;
-			rctx->finish = NULL;
 			rctx->next_server = true;
 		}