update check_case 11

The check case uses KGE for TWS which is not good because of small changes around zero have huge impacts on KGE (even within machine precision). See: !78 (comment 122705)

In branch develop_v6, this case is disabled for now. What options are there for a replacement?

Opti_function 15 uses KGE Q and RMSE TWS, this would be my first guess. However, opti_functions 28, 15 and 17 are already checked. So we skip it? Or update it, is KGE_q_KGE_ET_RMSE_TWS better, what are you currently using in the global runs @rakovec