When working with constraint sets, we track transitive relationships
between the constraints in the set. For instance, in `S ≤ int ∧ int ≤
T`, we can infer that `S ≤ T`. However, we should only consider fully
static types when looking for a "pivot" for this kind of transitive
relationship. The same pattern does not hold for `S ≤ Any ∧ Any ≤ T`;
because the two `Any`s can materialize to different types, we cannot
infer that `S ≤ T`.
Fixes https://github.com/astral-sh/ty/issues/2371