[2p2cni] update reference solutions

A lot has been changed in the test setting from the 2.12 release: boundary condition types, evaluation points for boundary condition values and spatial parameters, domain heterogeneity, complexity of the fluid system relations, Newton and linear solver tolerances, maximum time step size. Synchronizing the settings between 2.12 and master renders the differences negligibly small. Keep the new setting, uncomment the domain heterogeneity, simplify the Neumann boundary condition, adapt the reference solution.