OrcInputFormat.isOriginal() should not rely on hive.acid.key.index

org.apache.hadoop.hive.ql.io.orc.OrcInputFormat.isOriginal() is checking for presence of hive.acid.key.index in the footer. This is only created when the file is written by OrcRecordUpdater. It should instead check for presence of Acid metadata columns so that a file can be produced by something other than OrcRecordUpdater.

Also, hive.acid.key.index counts number of different type of events which is not really useful for Acid V2 (as of Hive 3) since each file only has 1 type of event.