Fix ExecutionMode's crashing drivers with compute based mesh output.
Fix ExecutionMode's crashing drivers with compute based mesh output.

The OpExecutionMode entries were being left in place, but pointing
to functions which are no longer entry points.  This caused the GPU
driver to crash (probably trying to look it up).

googlestadia/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,TurtleRockStudios/renderdoc_public,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,Zorro666/renderdoc,TurtleRockStudios/renderdoc_public,baldurk/renderdoc,Zorro666/renderdoc,googlestadia/renderdoc,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,Zorro666/renderdoc,googlestadia/renderdoc,baldurk/renderdoc,Zorro666/renderdoc,baldurk/renderdoc,TurtleRockStudios/renderdoc_public,googlestadia/renderdoc,baldurk/renderdoc