Remove the rest of ShaderDebugging.

Without UID checking, it's basically a no-op that disables shader cache
and stores the shader source code (without ever reading it back).

Source/Core/VideoCommon/VideoConfig.h

@@ -132,9 +132,6 @@ struct VideoConfig final
   // D3D only config, mostly to be merged into the above
   int iAdapter;
 
-  // Debugging
-  bool bEnableShaderDebugging;
-
   // VideoSW Debugging
   int drawStart;
   int drawEnd;