roachtest: unoptimized-query-oracle: missing cast to REGCLASS

roachtest.unoptimized-query-oracle/disable-rules=all/rand-tables [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyGceBazel/14927331?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyGceBazel/14927331?buildTab=artifacts#/unoptimized-query-oracle/disable-rules=all/rand-tables) on release-23.2 @ [d91ca866b265a837f832bc93b59481847d721f18](https://github.com/cockroachdb/cockroach/commits/d91ca866b265a837f832bc93b59481847d721f18):

```
(query_comparison_util.go:389).runOneRoundQueryComparison: . 1022 statements run: expected unoptimized and optimized results to be equal
[]string{
- ``e'\'tab{le2\'',ntehuv``,
+ "105,ntehuv",
}
sql: SELECT
(SELECT tab_29.col1_9 AS col_68 FROM defaultdb.public.table1@[0] AS tab_29 ORDER BY col_68 DESC LIMIT 1:::INT8)
AS col_69,
'ntehuv':::rand_typ_2 AS col_70
ORDER BY
col_70 DESC NULLS FIRST, col_69 DESC
LIMIT
72:::INT8
test artifacts and logs in: /artifacts/unoptimized-query-oracle/disable-rules=all/rand-tables/run_1
```

Parameters:
- ROACHTEST_arch=amd64
- ROACHTEST_cloud=gce
- ROACHTEST_coverageBuild=false
- ROACHTEST_cpu=4
- ROACHTEST_encrypted=false
- ROACHTEST_metamorphicBuild=false
- ROACHTEST_ssd=0
Help

See: [roachtest README](https://github.com/cockroachdb/cockroach/blob/master/pkg/cmd/roachtest/README.md)

See: [How To Investigate \(internal\)](https://cockroachlabs.atlassian.net/l/c/SSSBr8c7)

See: [Grafana](https://go.crdb.dev/roachtest-grafana/teamcity-14927331/unoptimized-query-oracle-disable-rules-all-rand-tables/1713782912220/1713783158546)

Same failure on other branches

- #122786 roachtest: unoptimized-query-oracle/disable-rules=all/rand-tables failed [C-test-failure O-roachtest O-robot T-sql-queries branch-release-23.1 release-blocker]

/cc @cockroachdb/sql-queries

[This test on roachdash](https://roachdash.crdb.dev/?filter=status:open%20t:.*unoptimized-query-oracle/disable-rules=all/rand-tables.*&sort=title+created&display=lastcommented+project) | [Improve this report!](https://github.com/cockroachdb/cockroach/tree/master/pkg/cmd/internal/issues)

Jira issue: CRDB-38067