lookupVar does not return the correct direction of variables

[Martin Sjölund]

I get the direction of i=Absyn.BIDIR() when I instantiate the following. That makes it quite hard to treat function input variables as parameters!

model M
  function f
    input Integer i;
    output Integer o[j];
  protected
    Integer j = i;
  algorithm
    o := fill(1,j);
  end f;
  Integer o[3] = f(3);
end M;

[Per Östlund]

With the new frontend the model is correctly flattened to:

model M
  function f
    input Integer i;
    output Integer o[j];
  protected
    Integer j = i;
  algorithm
    o := fill(1,j);
  end f;
  Integer o[3] = f(3);
end M;

The old frontend still can't handle this, but we don't care about that anymore.