Add skinnable test scene per ruleset to better allow dynamic compilation

osu.Game.Rulesets.Catch.Tests/CatchSkinnableTestScene.cs

@@ -0,0 +1,19 @@
+// Copyright (c) ppy Pty Ltd <contact@ppy.sh>. Licensed under the MIT Licence.
+// See the LICENCE file in the repository root for full licence text.
+
+using System;
+using System.Collections.Generic;
+using osu.Game.Rulesets.Catch.Skinning;
+using osu.Game.Tests.Visual;
+
+namespace osu.Game.Rulesets.Catch.Tests
+{
+    public abstract class CatchSkinnableTestScene : SkinnableTestScene
+    {
+        public override IReadOnlyList<Type> RequiredTypes => new[]
+        {
+            typeof(CatchRuleset),
+            typeof(CatchLegacySkinTransformer),
+        };
+    }
+}