basalt-26.3: roachtest: acceptance/mismatched-locality 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.acceptance/mismatched-locality [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_RedRoachtestNightlyGcePrivateBasaltBazel/21491312?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_RedRoachtestNightlyGcePrivateBasaltBazel/21491312?buildTab=artifacts#/acceptance/mismatched-locality) on basalt-26.3 @ [23c3d5a11cfe60e3d3650467f2be08b000eba5ef](https://github.com/cockroachdb/cockroach/commits/23c3d5a11cfe60e3d3650467f2be08b000eba5ef):

Failed with:

```
(mismatched_locality.go:34).runMismatchedLocalityTest: pq: region "east" does not exist
test artifacts and logs in: /artifacts/acceptance/mismatched-locality/run_1
```
Cluster Node to Ip Mapping:
| Node | Public IP | Private IP |
| --- | --- | --- |
| teamcity-21491312-1787983444-02-n3cpu4-0001 | | 10.91.111.204 |
| teamcity-21491312-1787983444-02-n3cpu4-0002 | | 10.91.111.203 |
| teamcity-21491312-1787983444-02-n3cpu4-0003 | | 10.91.111.202 |

Parameters:
- arch=amd64
- cloud=gce
- coverageBuild=false
- cpu=4
- diskCount=0
- encrypted=false
- fs=ext4
- localSSD=true
- metamorphicLeases=default
- 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-21491312/acceptance-mismatched-locality/1787983745717/1787983978655)

_Logs were not uploaded to Datadog_

/cc @cockroachlabs/sql-foundations

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

Start with pkg/cmd/roachtest/mismatched_locality.go at line 34 and inspect the linked TeamCity artifacts and logs for acceptance/mismatched-locality. Read the roachtest README for investigation guidance, then determine why region "east" does not exist in this run. Done means the mismatched-locality roachtest completes successfully without the reported database error.

Written by the indexing model from the issue text.