roachtest: ssh_problem failed

roachtest.ssh_problem [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyGceBazel/21422037?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_RoachtestNightlyGceBazel/21422037?buildTab=artifacts#/cdc/pubsub-sink) on release-26.1.8-rc @ [e3abeca7ec25cee7ec1962e9dc33131f74eaf950](https://github.com/cockroachdb/cockroach/commits/e3abeca7ec25cee7ec1962e9dc33131f74eaf950):

```
test cdc/pubsub-sink failed: (test_runner.go:1017).func4: not all nodes booted successfully: timed out after 5m: TRANSIENT_ERROR(ssh_problem): exit status 255 [owner=test-eng]
```

Parameters:
- cloud=gce
- coverageBuild=false
- cpu=16
- diskCount=0
- runtimeAssertionsBuild=false
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)

Same failure on other branches

- #172363 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-master]
- #172359 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-master]
- #171649 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.2.20-rc]
- #171630 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-26.1.6-rc]
- #171625 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.4.12-rc]
- #171529 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-24.1.30-rc]

/cc @cockroachlabs/test-eng

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

Jira issue: CRDB-65763

Start with the roachtest README and test_runner.go:1017, then inspect the linked TeamCity log and artifacts for cdc/pubsub-sink. Compare the failure with the related ssh_problem issues and determine why nodes fail to boot with TRANSIENT_ERROR(ssh_problem). Done means the cause is identified and the roachtest no longer reports this failure.

Written by the indexing model from the issue text.