roachtest: stage_failure 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.stage_failure [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyGceBazel/19606511?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyGceBazel/19606511?buildTab=artifacts#/jobs/mixed-versions) on release-25.2.0-rc @ [545da2936c70fdecb9bbbd652aa4bd90b8d26dad](https://github.com/cockroachdb/cockroach/commits/545da2936c70fdecb9bbbd652aa4bd90b8d26dad):

```
test jobs/mixed-versions failed: (mixedversion.go:829).Run: mixed-version test failure while running step 5 (restart node 1 with binary version v24.3.11): cluster.Stage: output:
curl: (92) HTTP/2 stream 0 was not closed cleanly: INTERNAL_ERROR (err 2)
gzip: stdin: unexpected end of file
tar: Unexpected EOF in archive
tar: Unexpected EOF in archive
tar: Error is not recoverable: exiting now: TRANSIENT_ERROR(stage_failure): COMMAND_PROBLEM: exit status 2 [owner=test-eng]
test artifacts and logs in: /artifacts/jobs/mixed-versions/run_1
```

Parameters:
- arch=amd64
- cloud=gce
- coverageBuild=false
- cpu=4
- encrypted=false
- fs=ext4
- localSSD=true
- metamorphicBufferedSender=true
- mvtDeploymentMode=system-only
- mvtVersions=v24.1.17 → v24.3.11 → release-25.2.0-rc
- runtimeAssertionsBuild=true
- 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-19606511/jobs-mixed-versions/1746268334620/1746268758922)

Same failure on other branches

- #140132 roachtest: stage_failure failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.1]
- #123276 roachtest: stage_failure failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-23.2]
- #123193 roachtest: stage_failure failed [O-roachtest O-robot T-testeng X-infra-flake branch-master]
- #123047 roachtest: stage_failure failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-24.1]

/cc @cockroachdb/test-eng

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

Jira issue: CRDB-50345

Start with pkg/cmd/roachtest/mixedversion.go at line 829 and the roachtest README, then inspect the linked TeamCity artifacts under /artifacts/jobs/mixed-versions/run_1 and the Grafana run. The report identifies a curl, gzip, and tar failure while restarting a node, but does not define a completion criterion beyond determining and resolving the recurring stage failure.

Written by the indexing model from the issue text.