Summary: Pull Request resolved: https://github.com/facebook/rocksdb/pull/11133

Test Plan:
- ran it a few times on a mismatching DB+expected state; verified error messages look right:

```
Verification failed for column family 0 key 000000000000D553000000000000014C0000000000000142 (163988): value_from_db: , value_from_expected: 25E7B53421202322, msg: GetMergeOperands verification: Value not found: NotFound:
Verification failed for column family 0 key 000000000000AAE2787878 (131123): value_from_db: , value_from_expected: B2A69C18B6B7B4B5BABBB8B9BEBFBCBDA2A3A0A1A6A7A4A5, msg: Iterator verification: Value not found: NotFound:
Verification failed for column family 0 key 00000000000080C6000000000000004C78787878 (98409): value_from_db: , value_from_expected: 67AB7E1E636261606F6E6D6C6B6A6968, msg: Get verification: Value not found: NotFound:
```

Reviewed By: hx235

Differential Revision: D42757072

Pulled By: ajkr

fbshipit-source-id: b0a4a0aaa5be5d110434324853ac92aaa6972d89