VideoCommon: Move some common initialization logic to RenderBase

Source/Core/VideoBackends/D3D12/Render.h

@@ -17,8 +17,8 @@ class D3DTexture2D;
 class Renderer final : public ::Renderer
 {
 public:
-  Renderer(void*& window_handle);
-  ~Renderer();
+  Renderer();
+  ~Renderer() override;
 
   void SetColorMask() override;
   void SetBlendMode(bool force_update) override;