[strub]

Fixes #1175.

When a functor is partially applied, Mod.unsuspend keeps the oracle
calls whose target is one of the remaining parameters. It compared the
full target of the call with the parameter, so a call such as
S(M).kg, whose target is S(M) and not S, was dropped even when
S is a remaining parameter.

The partial application then looked as if it made no call at all. In
the example of the issue, the following module is accepted at Adv,
whose run may call nothing:

module (B (D : T) : Adv) (S : Sch) = {
  proc run() : unit = { S(M).kg(); }
}.

and so is the instantiation of A <: Adv {-St} by B(M), which is
enough to prove false.

The filter now compares the functor of the target, as get_oi_calls
already does when it computes the calls of a module. ModTy.sig_of_mt
uses the same filter and is changed in the same way.