switched_map.parq was generated by modifying parquet-mr to switch the key and value fields
of map, and then converting switched_map.json to parquet using switched_map.avsc as the
schema. switched_map.parq has the following schema according to parquet-tools:

message org.apache.impala.switched_map {
  required group int_map (MAP) {
    repeated group map (MAP_KEY_VALUE) {
      required int32 value;
      required binary key (UTF8);
    }
  }
}