Strong frame drop due to calls of ovrp_WaitToBeginFrame

Hello!

ovrp_WaitToBeginFrame massively drops the FPS. This is famous trouble. The calls of this function impacts the performance with 13.5ms on my machine.

I removed call of FOculusHMD::StartGameFrame_GameThread (the function with ovrp_WaitToBeginFrame inside) in FOculusInput and this gave good result (normal flight, 80 FPS on Oculus Rift S). 

This function also calls in FOculusHMD::OnStartGameFrame with comment: "this should have already happened in FOculusInput, so this is usually a no-op" (lol?).

Ok. I ran the game also with Oculus Quest (via Oculus Link) on another machine, but again I got frame drop for now at FOculusHMD::OnStartGameFrame. So, this call of FOculusHMD::StartGameFrame_GameThread I can't remove due to it turns game to black screen.

So what can we do with it to get good performance? How soon it will be fixed? We wait.

Thanks, Artem.