[NF] Added prefixing test.

Belonging to [master]:
  - OpenModelica/OMCompiler#2456
  - OpenModelica/OpenModelica-testsuite#958

Author: perost

flattening/modelica/scodeinst/Makefile

@@ -569,6 +569,7 @@ OperatorOverloadError1.mo \
 PackageConstant1.mo \
 ParameterBug.mos \
 Prefix1.mo \
+Prefix2.mo \
 PropagateExtends.mo \
 RangeInvalidStep1.mo \
 RangeInvalidStep2.mo \

flattening/modelica/scodeinst/Prefix2.mo

@@ -0,0 +1,27 @@
+// name: Prefix2
+// keywords:
+// status: correct
+// cflags: -d=newInst
+//
+
+model A
+  Real x;
+end A;
+
+model B
+  Real y;
+  A a(x = y);
+end B;
+
+model Prefix2
+  B b[2];
+end Prefix2;
+
+// Result:
+// class Prefix2
+//   Real b[1].y;
+//   Real b[1].a.x = b[1].y;
+//   Real b[2].y;
+//   Real b[2].a.x = b[2].y;
+// end Prefix2;
+// endResult