roachtest: ssh_problem failed

roachtest.ssh_problem [failed](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_RoachtestNightlyGcePrivateBazel/21499504?buildTab=log) with [artifacts](https://teamcity.cockroachdb.com/buildConfiguration/Cockroach_Nightlies_Roachtests_RoachtestNightlyGcePrivateBazel/21499504?buildTab=artifacts#/backup/mvcc-range-tombstones) on release-25.4.17-rc @ [0447ee0a79bd81f5bcb15bcd613e6653dd0d1e0f](https://github.com/cockroachdb/cockroach/commits/0447ee0a79bd81f5bcb15bcd613e6653dd0d1e0f):

```
test backup/mvcc-range-tombstones failed: (test_runner.go:901).func4: cluster.PutE: put "/go/src/github.com/cockroachdb/cockroach/bin/cockroach.linux-arm64" failed: error persisted after 2 attempts: TRANSIENT_ERROR(ssh_problem): ~ scp -r -C -o StrictHostKeyChecking=no -o ConnectTimeout=10 -i /home/roach/.ssh/id_rsa /go/src/github.com/cockroachdb/cockroach/bin/cockroach.linux-arm64 ubuntu@10.91.80.32:./cockroach
Warning: Permanently added '10.91.80.32' (ECDSA) to the list of known hosts.
client_loop: send disconnect: Broken pipe
lost connection: exit status 1 [owner=test-eng]
```

Parameters:
- arch=arm64
- cloud=gce
- coverageBuild=false
- cpu=8
- encrypted=false
- fs=ext4
- localSSD=false
- runtimeAssertionsBuild=false
- 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-21499504/backup-mvcc-range-tombstones/-62135596800000/-62135596680000)

Same failure on other branches

- #173564 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.4.15-rc]
- #173555 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.2.23-rc]
- #172557 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.4.14-rc]
- #172517 roachtest: ssh_problem failed [O-roachtest O-robot T-testeng X-infra-flake branch-release-25.2.22-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)

Start with the failing backup/mvcc-range-tombstones artifact and the roachtest README at pkg/cmd/roachtest/README.md; inspect test_runner.go:901 and the linked Grafana data for the broken-pipe SSH failure. Use the internal investigation guide if available. Done means identifying the cause and verifying a reliable resolution for this recurring roachtest failure.

Written by the indexing model from the issue text.