Fix ElimComponentDefInst for nested def/inst

The cif validator crashes due to a bug in the eliminate component def/inst transformation for the following cif specification:

group def D():
  group e:
    group def F():
      v : V();
    end
  end
end

group def V():
end

d : D();

The problem is in the method findCompDefs, it incorrectly concludes that definition D() does not contain definitions or instantiations. That method cannot find definitions or instantiations contained within a group.