Addition of the saturationDensity function test

Media/SimpleMoistAir/test_saturationDensity.mo

+within TAeZoSysPro_testsuite.Media.SimpleMoistAir;
+
+model test_saturationDensity
+  parameter Modelica.SIunits.Temperature T = 303.15;
+  Modelica.SIunits.Density d_sat;
+  Modelica.SIunits.Density d_sat_IF97;
+equation
+  d_sat = saturationDensity(T);
+  d_sat_IF97 = Modelica.Media.Water.IF97_Utilities.BaseIF97.Regions.rhov_T(T);
+end test_saturationDensity;