ENG-6478: Allow LIMIT PARTITION ROWS to be set, changed, and dropped
using ALTER TABLE
ENG-6478: Review comment cleanups:
- Sanitize VoltDB-specific change comments in HSQL for easier
programmatic discovery
- Remove meaningless CASCADE token parsing
- Make test failures less opaque
Merge pull request #1727 from VoltDB/eng6478

ENG-6478: Allow LIMIT PARTITION ROWS to be set, changed, and dropped using ALTER TABLE syntax