message: Test that empty execute indirects don't crash
diff: @@ -147,6 +147,9 @@ float4 main() : SV_Target0
  .RTV()
  .InitialState(D3D12_RESOURCE_STATE_RENDER_TARGET);
  + ID3D12CommandSignaturePtr cmdsig = MakeCommandSig(NULL, {vbArg(0), drawArg()});
  + ID3D12ResourcePtr argBuf = MakeBuffer().Upload().Size(1024);
  +
  while(Running())
  {
  ID3D12GraphicsCommandListPtr cmd = GetCommandBuffer();
  @@ -206,6 +209,10 @@ float4 main() : SV_Target0
  cmd->DrawIndexedInstanced(3, 1, 0, 0, 0);
  + setMarker(cmd, "Empty indirect execute");
  +
  + cmd->ExecuteIndirect(cmdsig, 0, argBuf, 0, NULL, 0);
  +
  FinishUsingBackbuffer(cmd, D3D12_RESOURCE_STATE_RENDER_TARGET);
  if(debug)
  