Bug 1866596 - Use shorter timeout in HTTP/3 server, r=necko-reviewers,valentin

The current max timeout value used in h3 server is 1s, which is too long and causes the server stalls.
To fix the intermittent failrues, we should use a shorter timeout.

Differential Revision: https://phabricator.services.mozilla.com/D194773

netwerk/test/http3server/src/main.rs

@@ -1029,7 +1029,7 @@ fn process(
 
             qinfo!("Setting timeout of {:?} for {}", new_timeout, server);
             if new_timeout > Duration::from_secs(1) {
-                new_timeout = Duration::from_secs(1);
+                new_timeout = Duration::from_millis(500);
             }
             *svr_timeout = Some(timer.set_timeout(new_timeout, inx));
             false