bound regions affect path resolution

[aliemjay]

We should emit the same error message here regardless of whether the projection type contains bound regions.

fn test<'x>() {
    use std::ops::Deref;
    None::<for<'y> fn(<&'x Option<()> as Deref>::Target::Some)>;
    //~^ ERROR expected type, found variant
    None::<for<'y> fn(<&'y Option<()> as Deref>::Target::Some)>;
    //~^ ERROR ambiguous associated type
}

I discovered this in #101947 and added a FIXME comment.

@rustbot label T-compiler C-bug A-resolve