tests: Make TestRevisionCooker more modular
So its 'load' and 'check' parts can be reused for testing snapshots
Migrated from D5997 (view on Phabricator)
Staging instance, all changes can be removed at any time
So its 'load' and 'check' parts can be reused for testing snapshots
Migrated from D5997 (view on Phabricator)