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/21506130?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_RoachtestNightlyGcePrivateBazel/21506130?buildTab=artifacts#/schemachange/mixed-versions) on master @ [f3d9dd8405adad545c70b300675fef9e5e12e0cb](https://github.com/cockroachdb/cockroach/commits/f3d9dd8405adad545c70b300675fef9e5e12e0cb):

Failed with:

```
(mixedversion.go:1026).Run: mixed-version test failure while running step 38 (run "run schemachange workload and validation in mixed version"): full command output in run_063524.250316130_n4_COCKROACHRANDOMSEED6.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-21506130-1788933294-17-n4cpu4-0001 | | 10.91.97.172 |
| teamcity-21506130-1788933294-17-n4cpu4-0002 | | 10.91.97.174 |
| teamcity-21506130-1788933294-17-n4cpu4-0003 | | 10.91.97.173 |
| teamcity-21506130-1788933294-17-n4cpu4-0004 | | 10.91.96.87 |

Parameters:
- arch=amd64
- cloud=gce
- coverageBuild=false
- cpu=4
- diskCount=0
- encrypted=false
- mvtDeploymentMode=separate-process
- mvtVersions=v26.3.1 → v26.4.0-alpha.1-dev-f3d9dd8405adad545c70b300675fef9e5e12e0cb (master)
- 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-21506130/schemachange-mixed-versions/1788934809915/1788935914562)

See: [Datadog Logs](https://us5.datadoghq.com/logs?query=service%3Aroachtest+%40cluster%3Ateamcity-21506130-1788933294-17-n4cpu4&from_ts=1788934809915&to_ts=1788935914562&live=false&storage=flex_tier)

Same failure on other branches

- #173458 release-26.3: roachtest: schemachange/mixed-versions failed [B-runtime-assertions-enabled C-test-failure O-roachtest O-robot P-2 T-sql-foundations branch-release-26.3]

/cc @cockroachlabs/sql-foundations

[Improve this report!](https://github.com/cockroachdb/cockroach/tree/master/pkg/cmd/bazci/githubpost/issues)

Jira issue: CRDB-68079