This fixes #1109 (closed) .
We add a helper that decides on the constraintsolver to use to compute fugacities etc to use as initial conditions for the mpnc model based on if all phases are present or not
this does not work with the chemical non-equilibrium tests. Technically chemical non-equilibrium does not need to use a constraintsolver as not fugacities are the primary variables but mole fractions one can choose as one likes. The kinetic test only uses a constraintsolver as first the equilibrium state is calculated and then a deviation from that state is set as primary variables. Check if it makes sense to leave the chemical non-equilibrium test then as it is.
check thermalnonequilibrium test. why does this not work with the constraintsolver
Wrap FluidState in helper and provide setters for necessary stuff (pressures/saturations/moleFractions/temperature)