Use longer delay in test (#31072)

Author: BrennanConroy

src/Testing/test/TaskExtensionsTest.cs

@@ -2,6 +2,7 @@
 // Licensed under the Apache License, Version 2.0. See License.txt in the project root for license information.
 
 using System;
+using System.Threading;
 using System.Threading.Tasks;
 using Xunit;
 
@@ -12,7 +13,9 @@ public class TaskExtensionsTest
         [Fact]
         public async Task TimeoutAfterTest()
         {
-            await Assert.ThrowsAsync<TimeoutException>(async () => await Task.Delay(1000).TimeoutAfter(TimeSpan.FromMilliseconds(50)));
+            var cts = new CancellationTokenSource();
+            await Assert.ThrowsAsync<TimeoutException>(async () => await Task.Delay(30000, cts.Token).TimeoutAfter(TimeSpan.FromMilliseconds(50)));
+            cts.Cancel();
         }
     }
 }