Improved handling of non-scalarized bindings (#9685)

- Introduce the concept of an indexed prefix that can be used to flatten
  and vectorize non-scalarized bindings where they occur, instead of
  delaying it until `Flatten.vectorizeArray` where we don't know the
  correct prefix for each variable.
- Fix various minor issues with the non-scalarized flattening.

OMCompiler/Compiler/NFFrontEnd/NFCeval.mo

@@ -334,6 +334,7 @@ algorithm
         else
           // Crefs can be evaluated even if they have non-evaluated subscripts.
           outExp := evalCref(e.cref, e, target, evalSubscripts = false);
+          outEvaluated := Expression.isLiteral(outExp);
         end if;
       then
         outExp;

OMCompiler/Compiler/NFFrontEnd/NFConvertDAE.mo

@@ -1288,7 +1288,7 @@ algorithm
 
   binding := Component.getBinding(comp);
   binding := Binding.mapExp(binding, stripScopePrefixExp);
-  binding := Flatten.flattenBinding(binding, ComponentRef.EMPTY());
+  binding := Flatten.flattenBinding(binding, NFFlatten.EMPTY_PREFIX);
   bind_from_outside := Binding.source(binding) == NFBinding.Source.MODIFIER;
 
   ty := Component.getType(comp);

OMCompiler/Compiler/NFFrontEnd/NFEvalConstants.mo

@@ -110,7 +110,7 @@ algorithm
         eexp := Ceval.evalExp(exp, Ceval.EvalTarget.ATTRIBUTE(binding));
       end if;
 
-      eexp := Flatten.flattenExp(eexp, prefix);
+      eexp := Flatten.flattenExp(eexp, Flatten.PREFIX(prefix));
     else
       info := Binding.getInfo(binding);
       eexp := evaluateExp(exp, info);
@@ -183,7 +183,7 @@ algorithm
         if ComponentRef.nodeVariability(cref) <= Variability.STRUCTURAL_PARAMETER then
           // Evaluate all constants and structural parameters.
           outExp := Ceval.evalCref(cref, outExp, Ceval.EvalTarget.IGNORE_ERRORS(), evalSubscripts = false);
-          outExp := Flatten.flattenExp(outExp, cref);
+          outExp := Flatten.flattenExp(outExp, Flatten.Prefix.PREFIX(cref));
           outChanged := true;
         elseif outChanged then
           ty := ComponentRef.getSubscriptedType(cref);