Add test that waits indefinitely for test infrastructure validation

Co-authored-by: AndriySvyryd <6539701+AndriySvyryd@users.noreply.github.com>
Agent-Logs-Url: https://github.com/dotnet/efcore/sessions/293be4b9-917a-4e08-8b45-e9e347454117

Author: Copilot

test/EFCore.Tests/Infrastructure/TestInfrastructureTest.cs

@@ -0,0 +1,11 @@
+// Licensed to the .NET Foundation under one or more agreements.
+// The .NET Foundation licenses this file to you under the MIT license.
+
+namespace Microsoft.EntityFrameworkCore.Infrastructure;
+
+public class TestInfrastructureTest
+{
+    [ConditionalFact]
+    public async Task Waits_indefinitely()
+        => await Task.Delay(Timeout.InfiniteTimeSpan);
+}