Make dummy states derivatives bidirectional

- Fix ticket:5219

Belonging to [master]:
  - #2788

Author: lochel

Compiler/BackEnd/IndexReduction.mo

@@ -3691,7 +3691,7 @@ algorithm
         /* Dummy variables are algebraic variables, hence fixed = false */
         dattr = BackendVariable.getVariableAttributefromType(tp);
         odattr = DAEUtil.setFixedAttr(SOME(dattr), SOME(DAE.BCONST(false)));
-        dummy_derstate = BackendDAE.VAR(dummyderName,BackendDAE.DUMMY_DER(),dir,prl,tp,NONE(),NONE(),dim,source,odattr,ts,hideResult,comment,ct,io, false);
+        dummy_derstate = BackendDAE.VAR(dummyderName,BackendDAE.DUMMY_DER(),DAE.BIDIR(),prl,tp,NONE(),NONE(),dim,source,odattr,ts,hideResult,comment,ct,io, false);
         kind = if intEq(dn,0) then BackendDAE.DUMMY_STATE() else BackendDAE.DUMMY_DER();
         dummy_state = BackendDAE.VAR(name,kind,dir,prl,tp,NONE(),NONE(),dim,source,odattr,ts,hideResult,comment,ct,io, false);
         dummy_state = if intEq(dn,0) then inVar else dummy_state;