Partial revert, decouple TitleIDs.CurrentApplication from shader cache stuff; as I want that to ALWAYS reflect the current app.

src/Ryujinx.Graphics.Gpu/GraphicsConfig.cs

@@ -46,6 +46,12 @@ namespace Ryujinx.Graphics.Gpu
         /// Enables or disables high-level emulation of common GPU Macro code.
         /// </summary>
         public static bool EnableMacroHLE = true;
+        
+        /// <summary>
+        /// Title id of the current running game.
+        /// Used by the shader cache.
+        /// </summary>
+        public static string TitleId;
 
         /// <summary>
         /// Enables or disables the shader cache.

src/Ryujinx.Graphics.Gpu/Shader/ShaderCache.cs

@@ -117,8 +117,8 @@ namespace Ryujinx.Graphics.Gpu.Shader
         /// </summary>
         private static string GetDiskCachePath()
         {
-            return GraphicsConfig.EnableShaderCache && TitleIDs.CurrentApplication.HasValue
-                ? Path.Combine(AppDataManager.GamesDirPath, TitleIDs.CurrentApplication, "cache", "shader")
+            return GraphicsConfig.EnableShaderCache && GraphicsConfig.TitleId != null
+                ? Path.Combine(AppDataManager.GamesDirPath, GraphicsConfig.TitleId, "cache", "shader")
                 : null;
         }