enable valid xamlil test (disabled before because of portable.xaml)

tests/Avalonia.Markup.Xaml.UnitTests/Xaml/BasicTests.cs

@@ -721,11 +721,7 @@ namespace Avalonia.Markup.Xaml.UnitTests.Xaml
             }
         }
 
-
-        [Fact(Skip =
-@"Doesn't work with Portable.xaml, it's working in different creation order -
-Handled in test 'Control_Is_Added_To_Parent_Before_Final_EndInit'
-do we need it?")]
+        [Fact]
         public void Control_Is_Added_To_Parent_Before_Properties_Are_Set()
         {
             using (UnitTestApplication.Start(TestServices.StyledWindow))