Remove the `variable kind` heuristics introduced by commit:dd209d29.

types/type_tallying.ml

@@ -753,8 +753,6 @@ let apply_raw delta s t =
   );
 
   NormMemoHash.clear memo_norm;
-  let s = Substitution.kind delta Var.function_kind s in
-  let t = Substitution.kind delta Var.argument_kind t in 
   let vgamma = Var.mk "Gamma" in
   let gamma = var vgamma in
   let cgamma = cons gamma in