OrcFile.WriterOptions getOrcOptions() {
      return orcOptions;
    }
An extension to AcidOutputFormat that allows users to add additional
options.

todo: since this is only used for testing could we not control the writer some other way?
to simplify {@link #OrcRecordUpdater(Path, AcidOutputFormat.Options)}
ql/src/java/org/apache/hadoop/hive/ql/io/orc/OrcRecordUpdater.java