Summary:
We already exercised backup functionality in `db_stress` according to the `-backup_one_in` flag. This PR verifies the backup can be restored/opened and sanity checks a few keys. Changes in this PR:
- Extracted existing backup-related logic to a helper function, `TestBackupRestore`
- Added restore logic, which targets a hidden directory named "./.restore\<thread number\>", similar to how backups target hidden directories named "./.backup\<thread number\>".
- After restore, check the existence/non-existence of a few keys.
- With this PR, backup is no longer compatible with clearing column families.
- Also included unrelated fixes to set `ReadOptions::total_order_seek=true` when using `-compare_full_db_state_snapshot`
Pull Request resolved: https://github.com/facebook/rocksdb/pull/4655
Differential Revision: D12972496
Pulled By: ajkr
fbshipit-source-id: 481a40052d9a38d1bd5c5159aa4d7c5a4b546b80
8ba17f382e