Replace hardcoded database name from regression tests with :TEST_DBNAME
Remove creation of database single_2 from test runner and add it to
bgw_launcher and loader test since no other tests used those
use SQL comments in test scripts
Dropping a schema that a hypertable depends on should clean up
dependent metadata. There are two schemas that matter for hypertables:
the hypertable's schema and the associated schema where chunks are
stored.
This change deals with the above as follows:
- If the hypertable schema is dropped, the hypertable and all chunks
should be deleted as well, including metadata.
- If an associated schema is dropped, the hypertables that use that
associated schema will have their associated schemas reset to the
internal schema.
- Even if no hypertable currently uses the dropped schema as their
associated schema, there might be chunks that reside in the dropped
schema (e.g., if the associated schema was changed for their
hypertables), so those chunks should have the metadata deleted.
