Different handling of stop-comments on OCaml 4.03

[Julow]

The "attaching" of stop-comments changed in OCaml 4.04.2: ocaml/ocaml#872
With older versions, the module X won't be hidden in the following example because both stop-comments would be attached as attribute and would loose their relative positions:

(**/**)
module X : sig end
(**/**)

Was interpreted like:

(**/**)
(**/**)
module X : sig end

[jonludlam]

I don't think we need to fix this.

[asavahista]

makes sense but CI for tests should probably still be fixed somehow

[jonludlam]

Definitely, the fix for CI is straightforward!