[BE] Fix mixed-determined dump and raise index to 10

Belonging to [master]:
  - #2920

Author: kabdelhak

Compiler/BackEnd/Initialization.mo

@@ -1393,7 +1393,6 @@ algorithm
         //BackendDump.dumpEquationArray(eqns2, "remaining equations");
         DoubleEndedList.push_list_back(dumpVars, dumpVars2);
       end if;
-
       outEqSystem := BackendDAEUtil.setEqSystEqs(inEqSystem, eqns2);
       //print("index-" + intString(index) + " ende\n");
       //execStat("fixInitialSystem (initialization) [nEqns: " + intString(nEqns) + ", nAddEqs: " + intString(nAddEqs) + ", nAddVars: " + intString(nAddVars) + "]");

Compiler/Util/Error.mo

@@ -977,7 +977,7 @@ public constant Message VAR_NO_REMAINING_EQN = MESSAGE(582, SYMBOLIC(), WARNING(
 public constant Message MOVING_PARAMETER_BINDING_TO_INITIAL_EQ_SECTION = MESSAGE(583, TRANSLATION(), NOTIFICATION(),
   Util.gettext("Moving binding to initial equation section and setting fixed attribute of %s to false."));
 public constant Message MIXED_DETERMINED = MESSAGE(584, SYMBOLIC(), ERROR(),
-  Util.gettext("The given system is mixed-determined.   [index > %s]\nPlease checkout the option \"--maxMixedDeterminedIndex\"."));
+  Util.gettext("The initialization problem of given system is mixed-determined. It is under- as well as overdetermined and the mixed-determination-index is too high. [index > %s]\nPlease checkout the option \"--maxMixedDeterminedIndex\" to simulate with a higher threshold or consider changing some initial equations, fixed variables and start values."));
 public constant Message STACK_OVERFLOW_DETAILED = MESSAGE(584, SCRIPTING(), ERROR(),
   Util.gettext("Stack overflow occurred while evaluating %s:\n%s"));
 public constant Message NF_VECTOR_INVALID_DIMENSIONS = MESSAGE(585, TRANSLATION(), ERROR(),

Compiler/Util/Flags.mo

@@ -1280,7 +1280,7 @@ constant ConfigFlag INIT_OPT_MODULES = CONFIG_FLAG(77, "initOptModules",
   Util.gettext("Sets the initialization optimization modules to use in the back end. See --help=optmodules for more info."));
 
 constant ConfigFlag MAX_MIXED_DETERMINED_INDEX = CONFIG_FLAG(78, "maxMixedDeterminedIndex",
-  NONE(), EXTERNAL(), INT_FLAG(3), NONE(),
+  NONE(), EXTERNAL(), INT_FLAG(10), NONE(),
   Util.gettext("Sets the maximum mixed-determined index that is handled by the initialization."));
 constant ConfigFlag USE_LOCAL_DIRECTION = CONFIG_FLAG(79, "useLocalDirection",
   NONE(), EXTERNAL(), BOOL_FLAG(false), NONE(),