Update CountdownEventTest.cs

Author: WojciechNagorski

src/Renci.SshNet.Tests/Classes/Common/CountdownEventTest.cs

@@ -334,7 +334,10 @@ public void WaitHandle_WaitOne_ShouldReturnFalseWhenTimeoutExpiresBeforeCountdow
             Assert.IsFalse(actual);
             Assert.IsFalse(countdownEvent.IsSet);
             Assert.IsFalse(countdownEvent.WaitHandle.WaitOne(0));
-            Assert.IsTrue(watch.Elapsed >= timeout);
+            // Use precision because it fail in CI/CD pipeline on .NET 7. Locally it worked without precision.
+            // But I think it is not supper important because this is internal .NET implementation. 
+            var precision = TimeSpan.FromMilliseconds(6);
+            Assert.IsTrue(watch.Elapsed >= timeout.Subtract(precision));
 
             countdownEvent.Wait(Session.InfiniteTimeSpan);
             countdownEvent.Dispose();