Fixed deserializeJson() when input contains duplicate keys (fixes #1095)

extras/tests/JsonDeserializer/object.cpp

@@ -277,6 +277,7 @@ TEST_CASE("deserialize JSON object") {
       DeserializationError err = deserializeJson(doc, "{a:{b:{c:1}},a:2}");
 
       REQUIRE(err == DeserializationError::Ok);
+      REQUIRE(doc["a"] == 2);
     }
   }