[NF] Fix nfExpandOperations with unary ops.

Belonging to [master]:
  - #2633
  - OpenModelica/OpenModelica-testsuite#1023

Author: perost

Compiler/NFFrontEnd/NFExpandExp.mo

@@ -832,7 +832,13 @@ public
   function makeUnaryOp
     input Expression exp1;
     input Operator op;
-    output Expression exp = Expression.UNARY(op, exp1);
+    output Expression exp;
+  algorithm
+    if Expression.isScalarLiteral(exp1) then
+      exp := Ceval.evalUnaryOp(exp1, op);
+    else
+      exp := Expression.UNARY(op, exp1);
+    end if;
   end makeUnaryOp;
 
   function expandLogicalBinary

Compiler/NFFrontEnd/NFSimplifyExp.mo

@@ -292,7 +292,9 @@ algorithm
   Expression.UNARY(op, e) := unaryExp;
   se := simplify(e);
 
-  if Expression.isLiteral(se) then
+  if Flags.isSet(Flags.NF_EXPAND_OPERATIONS) then
+    unaryExp := ExpandExp.expand(ExpandExp.makeUnaryOp(se, op));
+  elseif Expression.isLiteral(se) then
     unaryExp := Ceval.evalUnaryOp(se, op);
   elseif not referenceEq(e, se) then
     unaryExp := Expression.UNARY(op, se);