basalt-26.3.2-rc-20260908: sql/row: TestRowFetcherMemoryLimits failed

sql/row.TestRowFetcherMemoryLimits [failed](https://mesolite.cluster.engflow.com/invocations/default/8e093717-3329-4dab-8a28-3ae7ce8b0293?testReportRun=2&testReportShard=1&testReportAttempt=1#targets-Ly9wa2cvc3FsL3Jvdzpyb3dfdGVzdA==) on basalt-26.3.2-rc-20260908 @ [807558e5e81666af257c811e925e4cae570abc28](https://github.com/cockroachdb/cockroach/commits/807558e5e81666af257c811e925e4cae570abc28):

```
=== RUN TestRowFetcherMemoryLimits
test_log_scope.go:172: test logs captured to: outputs.zip/logTestRowFetcherMemoryLimits3758714620
test_log_scope.go:82: use -show-logs to present logs inline
test_server_shim.go:639: DRPC is enabled (via testserver factory defaults)
```

Parameters:
- attempt=1
- race=true
- run=2
- shard=1
Help

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

Same failure on other branches

- #174871 basalt-26.3: sql/row: TestRowFetcherMemoryLimits failed [OOM] [C-test-failure O-robot T-sql-queries branch-basalt-26.3]
- #174861 sql/row: TestRowFetcherMemoryLimits failed [OOM] [C-test-failure O-robot T-sql-queries branch-master]
- #173436 sql/row: TestRowFetcherMemoryLimits failed [C-test-failure O-robot T-sql-queries branch-master]

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

Start with the linked test report and the sql/row TestRowFetcherMemoryLimits test, using the reported commit and parameters (race=true, run=2, shard=1, attempt=1) to reproduce the failure. Compare the related failures on basalt-26.3 and master, then identify the cause and make the test pass reliably on the affected branches.

Written by the indexing model from the issue text.