Describe the problem

Part of the schema change protocol requires a pre-commit hook where a bunch of stuff happens related to descriptor management and safety. When you use the internal executor API with a non-nil transaction, it bypasses the lifecycle
and state management which normally happens for SQL transactions. In particular, the deferred creation of jobs and
the checking of the two version invariant.

In the case of filetable, we see just that:

The intention here is good, but the outcome is dramatically bad. The end result is that the table does not have the foreign key that was intended and the descriptor is corrupt in that it references a job which was never created.

To Reproduce

Update as of 2022-09-20: 3c44cad fixes the bug that allowed the corruption to occur, but this issue should remain open to track work to fix any corruption that exists out in the wild.

CREATE DATABASE to_backup;
CREATE DATABASE backups;
BACKUP DATABASE to_backup INTO 'userfile://backups.public.userfiles_$user/data';
SELECT * FROM backups.crdb_internal.invalid_objects;

  id  | database_name | schema_name |            obj_name            |                     error
------+---------------+-------------+--------------------------------+-------------------------------------------------
  118 | backups       | public      | userfiles_$user_upload_payload | mutation job 737535981478510593: job not found

SELECT t->'mutationJobs', t->'mutations'
  FROM (
        SELECT crdb_internal.pb_to_json('desc', descriptor)->'table' AS t
          FROM system.descriptor
         WHERE id = '"userfiles_$user_upload_payload"'::REGCLASS
       );

[{"jobId": "737535981478510593", "mutationId": 1}]
[
  {
    "constraint": {
      "check": {
        "constraintId": 3
      },
      "constraintType": "FOREIGN_KEY",
      "foreignKey": {
        "constraintId": 3,
        "name": "file_id_fk",
        "originColumnIds": [
          1
        ],
        "originTableId": 118,
        "referencedColumnIds": [
          2
        ],
        "referencedTableId": 117,
        "validity": "Validating"
      },
      "name": "file_id_fk",
      "uniqueWithoutIndexConstraint": {
        "constraintId": 3
      }
    },
    "direction": "ADD",
    "mutationId": 1,
    "state": "DELETE_ONLY"
  }
]

Jira issue: CRDB-13265