basalt-26.3.2-rc-20260908: sql/stmtdiagnostics: TestTxnRegistry_InsertTxnRequest_Polling failed [OOM]

sql/stmtdiagnostics.TestTxnRegistry_InsertTxnRequest_Polling [failed](https://mesolite.cluster.engflow.com/invocations/default/5d15a619-5664-4606-90d0-90e2519cd159?testReportRun=1&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_Polling883797909
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=1
- shard=2
Help

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

Same failure on other branches

- #173423 sql/stmtdiagnostics: TestTxnRegistry_InsertTxnRequest_Polling failed [C-test-failure O-robot T-sql-queries branch-master]

[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 sql/stmtdiagnostics.TestTxnRegistry_InsertTxnRequest_Polling at commit 807558e5e81666af257c811e925e4cae570abc28 and inspect the linked test report and captured logs. Reproduce with the reported race=true, run=1, and shard=2 parameters, using -show-logs as needed. Done means identifying and resolving the OOM failure and confirming the test passes.

Written by the indexing model from the issue text.