Fix NoticesConnectFail

Old test mismatched heartbeats under load - this is local and server test friendly.

StackExchange.Redis.Tests/ConnectFailTimeout.cs

 using System.Threading;
+using System.Threading.Tasks;
 using Xunit;
 using Xunit.Abstractions;
 
@@ -10,28 +11,26 @@ public class ConnectFailTimeout : TestBase
 
 #if DEBUG
         [Fact]
-        public void NoticesConnectFail()
+        public async Task NoticesConnectFail()
         {
             SetExpectedAmbientFailureCount(-1);
             using (var conn = Create(allowAdmin: true))
             {
                 var server = conn.GetServer(conn.GetEndPoints()[0]);
-                conn.IgnoreConnect = true;
                 conn.ConnectionFailed += (s, a) =>
                     Output.WriteLine("Disconnected: " + EndPointCollection.ToString(a.EndPoint));
                 conn.ConnectionRestored += (s, a) =>
                     Output.WriteLine("Reconnected: " + EndPointCollection.ToString(a.EndPoint));
-                server.SimulateConnectionFailure();
-                Thread.Sleep(2000);
-                try
-                {
-                    server.Ping();
-                    Assert.True(false, "Did not expect PING to succeed");
-                }
-                catch (RedisConnectionException) { /* expected */ }
 
+                // No need to delay, we're going to try a disconnected connection immediately so it'll fail...
+                conn.IgnoreConnect = true;
+                server.SimulateConnectionFailure();
                 conn.IgnoreConnect = false;
-                Thread.Sleep(2000);
+                Assert.Throws<RedisConnectionException>(() => server.Ping());
+
+                // Heartbeat should reconnect by now
+                await Task.Delay(5000);
+
                 var time = server.Ping();
                 Output.WriteLine(time.ToString());
             }