DRILL-7565: ANALYZE TABLE ... REFRESH METADATA does not work for empty Parquet files
- Fixed ConvertMetadataAggregateToDirectScanRule rule to distinguish array columns correctly and proceed using other parquet metadata if such columns are found.
- Added new implicit column which signalizes whether the empty result is obtained during collecting metadata and helps to distinguish real data results from metadata results.
- Updated scan to return row with metadata if the above implicit column is present.
- Added unit tests for checking the correctness of both optional and required columns from empty files.
closes #1985
