HIVE-14035 etc introduced a more efficient data layout for acid tables
Additional work is needed to support Merge for these tables
Need to make sure we generate unique ROW_IDs in each branch of the multi-insert statement. StatementId was introduced in
HIVE-11030 but it's not surfaced from storage layer. It needs to be made part of ROWID to ensure unique ROW_ID from concurrent writes from the same query.