Discard debug messages after starting the frame capture
Discard debug messages after starting the frame capture

* This prevents us from serialising debug messages caused by the
  initial state preparation accidentally.

Zorro666/renderdoc,michaelrgb/renderdoc,TurtleRockStudios/renderdoc_public,etnlGD/renderdoc,baldurk/renderdoc,etnlGD/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,cgmb/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,michaelrgb/renderdoc,googlestadia/renderdoc,Zorro666/renderdoc,Zorro666/renderdoc,michaelrgb/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,googlestadia/renderdoc,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,etnlGD/renderdoc,cgmb/renderdoc,TurtleRockStudios/renderdoc_public,etnlGD/renderdoc,michaelrgb/renderdoc,cgmb/renderdoc,googlestadia/renderdoc,Zorro666/renderdoc,googlestadia/renderdoc,cgmb/renderdoc,etnlGD/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,etnlGD/renderdoc,baldurk/renderdoc,michaelrgb/renderdoc,googlestadia/renderdoc,cgmb/renderdoc