DRILL-4725: Improvements to InfoSchema RecordGenerator needed for DRILL-4714
1. Add support for pushing the filter on following fields into InfoSchemaRecordGenerator:
- CATALOG_NAME
- COLUMN_NAME
2. Pushdown LIKE with ESCAPE. Add test TestInfoSchemaFilterPushDown#testFilterPushdown_LikeWithEscape
3. Add a method visitCatalog() to InfoSchemaRecordGenerator to decide whether to explore the catalog or not
4. Refactor CATALOG_DESCRIPTION and CATALOG_CONNECT as constant strings in InfoSchemaConstants.java
5. Update TestInfoSchemaFilterPushDown#testPartialFilterPushDownWithProject as
we are now pushing the filter on COLUMN_NAME field
6. Cleanup:
Rename RecordGenerator -> InfoSchemaRecordGenerator
Add comments in RecordGenerator
Rename SelectedTable -> InfoSchemaTableType
this closes #524
Change-Id: I0b2e16d04cb72fe3ce5961f5f357a00655f1cb05
