Fix parsing of return type as param in blocks

This fix was partially done in a6e9274
but limited itself to loop types, even though the behavior is the same
for blocks and loops.

src/parser/binary_parser.ml

@@ -316,7 +316,7 @@ let read_FC input =
     (Table_fill tableidx, input)
   | i -> Error (`Msg (Format.sprintf "illegal opcode (1) %i" i))
 
-let read_block_type ~is_loop types input =
+let read_block_type types input =
   match read_S33 input with
   | Ok (i, input) when i >= 0L ->
     let block_type = types.(Int64.to_int i) in
@@ -326,7 +326,7 @@ let read_block_type ~is_loop types input =
     | Ok ('\x40', input) -> Ok (Bt_raw (None, ([], [])), input)
     | Error _ | Ok _ ->
       let* vt, input = read_valtype input in
-      let pt, rt = if is_loop then ([], [ vt ]) else ([ (None, vt) ], []) in
+      let pt, rt = ([], [ vt ]) in
       Ok (Bt_raw (None, (pt, rt)), input)
   end
 
@@ -337,17 +337,17 @@ let rec read_instr types input =
   | '\x00' -> Ok (Unreachable, input)
   | '\x01' -> Ok (Nop, input)
   | '\x02' ->
-    let* bt, input = read_block_type ~is_loop:false types input in
+    let* bt, input = read_block_type types input in
     let* expr, input = read_expr types input in
     let+ input = check_end_opcode input in
     (Block (None, Some bt, expr), input)
   | '\x03' ->
-    let* bt, input = read_block_type ~is_loop:true types input in
+    let* bt, input = read_block_type types input in
     let* expr, input = read_expr types input in
     let+ input = check_end_opcode input in
     (Loop (None, Some bt, expr), input)
   | '\x04' ->
-    let* bt, input = read_block_type ~is_loop:false types input in
+    let* bt, input = read_block_type types input in
     let* expr1, input = read_expr types input in
     let* expr2, input =
       begin