The NF does not compute variability correctly in Modelica.Media

[casella]

Please check ​Modelica.Media.Examples.TestOnly.IdealGasN2Mix. The following error is issued by the NF

[Modelica trunk/Media/IdealGases/Common/package.mo:634:3-634:69:writable] Error:
Component MMX of variability constant has binding 'Medium.data[:].MM'
of higher variability continuous.

The ​offending line reads

constant MolarMass[nX] MMX=data[:].MM "Molar masses of components";

with

  constant Modelica.Media.IdealGases.Common.DataRecord[:] data
    "Data records of ideal gas substances";

which is constant, contrary to what the error message says.

[casella]

This problem is now fixed, the model fails because of #5201