Downgrade "timeout" and "attempts" arguments in shutdown

The shutdown system test sends queries when named is shutting down, not
in an attempt to get answers but to destabilize the server into a crash.
With isctest.query.udp() defaulting to try up to ten times with a
ten-second timeout to get a response we don't care about from a likely
terminated server, we make the test run much longer than needed because
of retries and long timeouts.

(cherry picked from commit 463ab2f3f5)

bin/tests/system/shutdown/tests_shutdown.py

@@ -101,7 +101,11 @@ def do_work(named_proc, resolver_ip, instance, kill_method, n_workers, n_queries
 
                 qname = relname + ".test"
                 msg = dns.message.make_query(qname, "A")
-                futures[executor.submit(isctest.query.udp, msg, resolver_ip)] = tag
+                futures[
+                    executor.submit(
+                        isctest.query.udp, msg, resolver_ip, timeout=1, attempts=1
+                    )
+                ] = tag
             elif shutdown:  # We attempt to stop named in the middle
                 shutdown = False
                 if kill_method == "rndc":