test fixes

Author: kevmoo

json_serializable/test/kitchen_sink/kitchen_sink_test.dart

@@ -294,7 +294,11 @@ const _nonNullableFields = {
   'strictKeysObject'
 };
 
-const _encodedAsMapKeys = {'simpleObject', 'strictKeysObject'};
+const _encodedAsMapKeys = {
+  'simpleObject',
+  'strictKeysObject',
+  'recordField',
+};
 
 const _iterableMapKeys = {
   'bigIntMap',

json_serializable/test/kitchen_sink/kitchen_sink_test_shared.dart

@@ -82,7 +82,12 @@ const invalidValueTypes = {
     'value': 10,
     'invalid_key': true,
   },
-  'validatedPropertyNo42': true
+  'validatedPropertyNo42': true,
+  'recordField': {
+    '\$1': 1,
+    '\$2': 'other string',
+    'truth': false,
+  },
 };
 
 const disallowNullKeys = {