release-26.3: roachtest: schemachange/mixed-versions failed

**Note:** This build has runtime assertions enabled. If the same failure was hit in a run without assertions enabled, there should be a similar failure without this message. If there isn't one, then this failure is likely due to an assertion violation or (assertion) timeout.

roachtest.schemachange/mixed-versions [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_RoachtestNightlyGcePrivateBazel/21470091?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_RoachtestNightlyGcePrivateBazel/21470091?buildTab=artifacts#/schemachange/mixed-versions) on release-26.3 @ [2367ea5f73ff9d1e43cd1ea5b811afe886c96bca](https://github.com/cockroachdb/cockroach/commits/2367ea5f73ff9d1e43cd1ea5b811afe886c96bca):

Failed with:

```
(mixedversion.go:926).Run: mixed-version test failure while running step 19 (run "run schemachange workload and validation in mixed version"): full command output in run_075038.519139844_n4_COCKROACHRANDOMSEED8.log: COMMAND_PROBLEM: exit status 1
test artifacts and logs in: /artifacts/schemachange/mixed-versions/run_1
```
Cluster Node to Ip Mapping:
| Node | Public IP | Private IP |
| --- | --- | --- |
| teamcity-21470091-1787035208-23-n4cpu4-0001 | | 10.91.97.95 |
| teamcity-21470091-1787035208-23-n4cpu4-0002 | | 10.91.97.53 |
| teamcity-21470091-1787035208-23-n4cpu4-0003 | | 10.91.97.96 |
| teamcity-21470091-1787035208-23-n4cpu4-0004 | | 10.91.97.102 |

Parameters:
- arch=amd64
- cloud=gce
- coverageBuild=false
- cpu=4
- diskCount=0
- encrypted=false
- mvtDeploymentMode=separate-process
- mvtVersions=v26.2.1 → v26.3.1-dev-2367ea5f73ff9d1e43cd1ea5b811afe886c96bca (release-26.3)
- runtimeAssertionsBuild=true
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-21470091/schemachange-mixed-versions/1787039148213/1787039689319)

See: [Datadog Logs](https://us5.datadoghq.com/logs?query=service%3Aroachtest+%40cluster%3Ateamcity-21470091-1787035208-23-n4cpu4&from_ts=1787039148213&to_ts=1787039689319&live=false&storage=flex_tier)

/cc @cockroachlabs/sql-foundations

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

Jira issue: CRDB-66775