Remove the runtime XAML loader from the tests

tests/Avalonia.ReactiveUI.UnitTests/AvaloniaActivationForViewFetcherTest.cs

@@ -74,36 +74,18 @@ namespace Avalonia.ReactiveUI.UnitTests
         {
             public ActivatableWindow()
             {
-                InitializeComponent();
-                Assert.IsType<Border>(Content);
+                Content = new Border();
                 this.WhenActivated(disposables => { });
             }
-
-            private void InitializeComponent()
-            {
-                AvaloniaRuntimeXamlLoader.Load(@"
-<Window xmlns='https://github.com/avaloniaui'>
-    <Border/>
-</Window>", null, this);
-            }
         }
 
         public class ActivatableUserControl : ReactiveUserControl<ActivatableViewModel>
         {
             public ActivatableUserControl()
             {
-                InitializeComponent();
-                Assert.IsType<Border>(Content);
+                Content = new Border();
                 this.WhenActivated(disposables => { });
             }
-
-            private void InitializeComponent()
-            {
-                AvaloniaRuntimeXamlLoader.Load(@"
-<UserControl xmlns='https://github.com/avaloniaui'>
-    <Border/>
-</UserControl>", null, this);
-            }
         }
 
         public AvaloniaActivationForViewFetcherTest()