DRILL-7064: Leverage the summary metadata for plain COUNT aggregates.
Add unit test
Modify MetadataDirectGroupScan to track summary file information and use in unit test.
Conflicts:
exec/java-exec/src/main/java/org/apache/drill/exec/store/parquet/metadata/Metadata.java
exec/java-exec/src/main/java/org/apache/drill/exec/store/parquet/metadata/Metadata_V4.java
Fix NPE for DrillTable to account for non-eligible tables.
Fix bug with direct scan after directory pruning. Add unit test.
Address review comments.
closes #1736
