The tests in restbase-mod-table-cassandra aren't specific to Cassandra, they are applicable to any interface-matching table storage backend. T88191 is an example of such a backend, and could benefit from these tests being reusable.

Steps (WIP)

1. The tests, and table spec, should be moved from restbase-mod-table-cassandra into a new npm module (restbase-mod-table-spec).
2. Add a restbase-mod-table-cassandra dependency on restbase-mod-table-spec, and import/load spec from there
3. Move dbutils#testTidFromDate to restbase-mod-table-spec
4. Move the final two tests in test/revision_policies.js into test/dbutils.js (dependencies on dbutil#validateAndNormalizeRevPolicy and dbutil#validateAndNormalizeSchema).
5. Start up a service exposing the module, using service-runner and RESTBase (with a custom config.yaml for the implementation)
6. Run imported tests from restbase-mod-table-cassandra against this server