[Equil/Test] Fix failures involving use of global variables

Direct use of "global" variables defined in the shared library results in
inconsistent behavior.

include/cantera/equil/vcs_MultiPhaseEquil.h

@@ -370,6 +370,8 @@ protected:
  * Default is to allow printing. But, you can assign this to zero globally to
  * turn off all time printing. This is helpful for test suite purposes where
  * you are interested in differences in text files.
+ * @deprecated Call `VCS_SOLVE::disable_timing()` instead. To be removed after
+ *     Cantera 2.3.
  */
 extern int vcs_timing_print_lvl;
 

include/cantera/equil/vcs_solve.h

@@ -1866,6 +1866,10 @@ public:
      */
     int m_timing_print_lvl;
 
+    //! Disable printing of timing information. Used to generate consistent
+    //! output for tests.
+    static void disableTiming();
+
     friend class vcs_phaseStabilitySolve;
 };
 

src/equil/vcs_solve.cpp

@@ -825,4 +825,8 @@ double VCS_SOLVE::vcs_VolTotal(const double tkelvin, const double pres,
     return VolTot;
 }
 
+void VCS_SOLVE::disableTiming() {
+    vcs_timing_print_lvl = 0;
+}
+
 }

test_problems/VCSnonideal/LatticeSolid_LiSi/latsol.cpp

@@ -12,7 +12,7 @@ using namespace Cantera;
 void testProblem(int printLvl)
 {
     double T = 273.15 + 352.0;
-    vcs_timing_print_lvl = 0;
+    VCS_SOLVE::disableTiming();
 
     // Create the phases
     std::unique_ptr<ThermoPhase> LiSi_solid(newPhase("Li7Si3_ls.xml",

test_problems/VCSnonideal/NaCl_equil/nacl_equil.cpp

@@ -33,7 +33,7 @@ int main(int argc, char** argv)
     int numFail = 0;
     int printLvl = 1;
     string inputFile = "HMW_NaCl.xml";
-    vcs_timing_print_lvl = 0;
+    VCS_SOLVE::disableTiming();
 
     /*
      * Process the command line arguments