UPBGE: Disable temporarly source of unstabilty in master

As there's vulkan integration on the way, as I might need to debug
avoiding "interferences", as I currently work with AMD CPU which can
cause issues even with an nvidia card, and as AMD CPU + AMD igpu combo
seems even more unstable with GPU_finish() or fences

source/blender/draw/intern/draw_cache_impl_mesh.cc

@@ -1945,12 +1945,12 @@ void DRW_mesh_batch_cache_create_requested(TaskGraph *task_graph,
  /* UPBGE: Even if it can create unstabilties in rare cases on some hardwares (never noticed with an intel CPU),
  * it's worth (performances-wise) using GPU_finish() or a fence here instead of BLI_task_graph_work_and_wait(task_graph);
  * Using a fence works even better on some hardwares. */
- //BLI_task_graph_work_and_wait(task_graph);
+ BLI_task_graph_work_and_wait(task_graph);
  //GPU_finish();
- GPUFence *fence = GPU_fence_create();
- GPU_fence_signal(fence);
- GPU_fence_wait(fence);
- GPU_fence_free(fence);
+ //GPUFence *fence = GPU_fence_create();
+ //GPU_fence_signal(fence);
+ //GPU_fence_wait(fence);
+ //GPU_fence_free(fence);
 
 #ifdef DEBUG
  drw_mesh_batch_cache_check_available(task_graph, me);