Fix singleton record calldata decode + test

test/aeso_calldata_tests.erl

@@ -113,6 +113,7 @@ compilable_contracts() ->
      {"funargs", "traffic_light", ["Pantone(12)"]},
      {"funargs", "tuples", ["()"]},
      %% TODO {"funargs", "due", ["FixedTTL(1020)"]},
+     {"funargs", "singleton_rec", ["{x = 1000}"]},
      {"variant_types", "init", []},
      {"basic_auth", "init", []},
      {"address_literals", "init", []},

test/contracts/funargs.aes

@@ -45,3 +45,8 @@ contract FunctionArguments =
 
   entrypoint due(t : Chain.ttl) =
      true
+
+  record singleton_r = { x : int }
+
+  entrypoint singleton_rec(r : singleton_r) =
+    r.x