video_core: disable depth/stencil texture download on OpenGL ES

src/video_core/renderer_opengl/texture_downloader_es.cpp

@@ -223,6 +223,8 @@ void TextureDownloaderES::GetTexImage(GLenum target, GLuint level, GLenum format
     switch (format) {
     case GL_DEPTH_COMPONENT:
     case GL_DEPTH_STENCIL:
+        // unfortunately, the accurate way is too slow for release
+        return;
         state.draw.read_framebuffer = ConvertDepthToColor(level, format, type, height, width);
         state.Apply();
         break;