Fix a bug in the Brzozowski demo, reported by Chet Murthy.

Regular expressions were not correctly canonicalized.

demos/brz/Brzozowski.ml

@@ -232,7 +232,7 @@ let disjunction (es : regexp list) : regexp =
   (* [1 ||| e] is [1]. *)
   if exists universal es then one else
   (* Disjunction is ACI. *)
-  let es = es |> undisj |> uniq compare |> sort compare in
+  let es = es |> undisj |> sort compare |> uniq compare in
   (* Avoid disjunctions of one element. *)
   match es with [e] -> e | _ -> make (EDisj es)
 
@@ -256,7 +256,7 @@ let conjunction (es : regexp list) : regexp =
   (* [0 &&& e] is [0]. *)
   if exists empty es then zero else
   (* Conjunction is ACI. *)
-  let es = es |> unconj |> uniq compare |> sort compare in
+  let es = es |> unconj |> sort compare |> uniq compare in
   (* Avoid conjunctions of one element. *)
   match es with [e] -> e | _ -> make (EConj es)