add an example where we unify the self type of a class with the one of an object
add an example where we unify the self type of a class with the one of an object

We will then happily close the type of the object, and die in atrocious
suffering when trying to generalize the row variable of the class' self type.

gerdstolpmann/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml,gerdstolpmann/ocaml