=str: #16285: Expand should not drop elements on completion

interestingly the PhantomDirective is not working that way, it gives scala.runtime.Null$, changing the type to FreeDirective gives

    Code:
           0: aload_0
           1: getfield      #19                 // Field PhantomDirective:Lakka/stream/stage/FreeDirective;
           4: areturn

and we have a

    private final akka.stream.stage.FreeDirective PhantomDirective;