Set ShutdownTimeout in Kestrel tests (#25743)

src/Servers/Kestrel/shared/test/TransportTestHelpers/TestServer.cs

@@ -101,6 +101,13 @@ namespace Microsoft.AspNetCore.Server.Kestrel.FunctionalTests
                         .UseSetting(WebHostDefaults.ShutdownTimeoutKey, TestConstants.DefaultTimeout.TotalSeconds.ToString())
                         .Configure(app => { app.Run(_app); });
                 })
+                .ConfigureServices(services =>
+                {
+                    services.Configure<HostOptions>(option =>
+                    {
+                        option.ShutdownTimeout = TestConstants.DefaultTimeout;
+                    });
+                })
                 .Build();
 
             _host.Start();