basalt-26.3.2-rc-20260908: sql/stmtdiagnostics: TestTxnRegistry_InsertTxnRequest_Polling failed

sql/stmtdiagnostics.TestTxnRegistry_InsertTxnRequest_Polling [failed](https://mesolite.cluster.engflow.com/invocations/default/bb2803f0-20da-4132-9bf9-2818a577ee69?testReportRun=3&testReportShard=2&testReportAttempt=1#targets-Ly9wa2cvc3FsL3N0bXRkaWFnbm9zdGljczpzdG10ZGlhZ25vc3RpY3NfdGVzdA==) on basalt-26.3.2-rc-20260908 @ [807558e5e81666af257c811e925e4cae570abc28](https://github.com/cockroachdb/cockroach/commits/807558e5e81666af257c811e925e4cae570abc28):

```
=== RUN TestTxnRegistry_InsertTxnRequest_Polling
test_log_scope.go:172: test logs captured to: outputs.zip/logTestTxnRegistry_InsertTxnRequest_Polling116043919
test_log_scope.go:82: use -show-logs to present logs inline
test_server_shim.go:168: automatically injected an external process virtual cluster under test; see comment at top of test_server_shim.go for details.
```

Parameters:
- attempt=1
- race=true
- run=3
- shard=2
Help

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

[This test on roachdash](https://roachdash.crdb.dev/?filter=status:open%20t:.*TestTxnRegistry_InsertTxnRequest_Polling.*&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 captured logs for TestTxnRegistry_InsertTxnRequest_Polling in sql/stmtdiagnostics, then inspect test_server_shim.go as referenced by the failure output. Re-run the test with race detection to reproduce the failure. Done means the cause is identified, the failure is fixed, and the test passes reliably.

Written by the indexing model from the issue text.