ccl/changefeedccl: TestChangefeedBackfillCheckpoint failed

ccl/changefeedccl.TestChangefeedBackfillCheckpoint [failed](https://mesolite.cluster.engflow.com/invocations/default/a0de4f0e-960c-4426-bb73-748b91f8a108?testReportRun=1&testReportShard=7&testReportAttempt=1#targets-Ly9wa2cvY2NsL2NoYW5nZWZlZWRjY2w6Y2hhbmdlZmVlZGNjbF90ZXN0) on release-26.1 @ [590b5b95ded9f09f1c370bfb0b0a7226ce5c1f14](https://github.com/cockroachdb/cockroach/commits/590b5b95ded9f09f1c370bfb0b0a7226ce5c1f14):

```
| foo: [959]->{"after": {"a": 959, "b": "d"}}
| foo: [960]->{"after": {"a": 960}}
| foo: [961]->{"after": {"a": 961, "b": "d"}}
| foo: [962]->{"after": {"a": 962}}
| foo: [963]->{"after": {"a": 963}}
| foo: [964]->{"after": {"a": 964}}
| foo: [965]->{"after": {"a": 965}}
| foo: [966]->{"after": {"a": 966, "b": "d"}}
| foo: [967]->{"after": {"a": 967}}
| foo: [968]->{"after": {"a": 968}}
| foo: [969]->{"after": {"a": 969, "b": "d"}}
| foo: [96]->{"after": {"a": 96, "b": "d"}}
| foo: [96]->{"after": {"a": 96}}
| foo: [970]->{"after": {"a": 970, "b": "d"}}
| foo: [971]->{"after": {"a": 971}}
| foo: [972]->{"after": {"a": 972}}
| foo: [973]->{"after": {"a": 973}}
| foo: [974]->{"after": {"a": 974, "b": "d"}}
| foo: [975]->{"after": {"a": 975}}
| foo: [976]->{"after": {"a": 976, "b": "d"}}
| foo: [977]->{"after": {"a": 977}}
| foo: [978]->{"after": {"a": 978}}
| foo: [979]->{"after": {"a": 979}}
| foo: [97]->{"after": {"a": 97}}
| foo: [980]->{"after": {"a": 980}}
| foo: [981]->{"after": {"a": 981}}
| foo: [982]->{"after": {"a": 982, "b": "d"}}
| foo: [983]->{"after": {"a": 983}}
| foo: [984]->{"after": {"a": 984}}
| foo: [985]->{"after": {"a": 985, "b": "d"}}
| foo: [986]->{"after": {"a": 986, "b": "d"}}
| foo: [987]->{"after": {"a": 987}}
| foo: [988]->{"after": {"a": 988}}
| foo: [989]->{"after": {"a": 989, "b": "d"}}
| foo: [98]->{"after": {"a": 98, "b": "d"}}
| foo: [990]->{"after": {"a": 990, "b": "d"}}
| foo: [991]->{"after": {"a": 991}}
| foo: [992]->{"after": {"a": 992}}
| foo: [993]->{"after": {"a": 993, "b": "d"}}
| foo: [994]->{"after": {"a": 994}}
| foo: [995]->{"after": {"a": 995}}
| foo: [996]->{"after": {"a": 996, "b": "d"}}
| foo: [997]->{"after": {"a": 997, "b": "d"}}
| foo: [998]->{"after": {"a": 998, "b": "d"}}
| foo: [999]->{"after": {"a": 999}}
| foo: [99]->{"after": {"a": 99}}
| foo: [9]->{"after": {"a": 9, "b": "d"}}
Error types: (1) *withstack.withStack (2) *errutil.leafError
Test: TestChangefeedBackfillCheckpoint/enterprise/limit=100_B
--- FAIL: TestChangefeedBackfillCheckpoint/enterprise/limit=100_B (10.87s)
```

Parameters:
- attempt=1
- run=1
- shard=7
Help

See also: [How To Investigate a Go Test Failure \(internal\)](https://cockroachlabs.atlassian.net/l/c/HgfXfJgM)

/cc @cockroachdb/cdc

[This test on roachdash](https://roachdash.crdb.dev/?filter=status:open%20t:.*TestChangefeedBackfillCheckpoint.*&sort=title+created&display=lastcommented+project) | [Improve this report!](https://github.com/cockroachdb/cockroach/tree/master/pkg/cmd/bazci/githubpost/issues)

Jira issue: CRDB-57963