[brineco2][tests] disable brineco2-test phase restriction and make brineco2 non-ideal mixture
The BrineCO2 fluidsystem is not compatible with the restrictToPhase
we use for all other tests because the fugacity coefficients are calculated using the other phases' composition.
We also realized that BrineCO2 is not an ideal mixture in the wetting-phase case.
Fixes #561 (closed)
Edited by Simon Emmert