integration: TestV3LeaseCheckpoint is flaky

[tbg]

https://travis-ci.com/etcd-io/etcd/jobs/225500520

--- PASS: TestV3LeaseKeepAlive (0.19s)

=== RUN   TestV3LeaseCheckpoint

{"level":"warn","ts":"2019-08-15T11:46:31.071Z","caller":"clientv3/retry_interceptor.go:61","msg":"retrying of unary invoker failed","target":"endpoint://client-60c901d5-3297-4d28-8c33-ea044ad70988/localhost:49286290045408381770","attempt":0,"error":"rpc error: code = Unavailable desc = etcdserver: request timed out"}

--- FAIL: TestV3LeaseCheckpoint (5.41s)

    v3_lease_test.go:246: rpc error: code = Unavailable desc = etcdserver: request timed out

[stale]

This issue has been automatically marked as stale because it has not had recent activity. It will be closed after 21 days if no further activity occurs. Thank you for your contributions.

[tjungblu]

just happened on PR #17943:
https://github.com/etcd-io/etcd/actions/runs/8967018597/job/24623684470#step:6:1887

--- FAIL: TestV3LeaseCheckpoint (72.06s)
--- FAIL: TestV3LeaseCheckpoint/Checkpointing_enabled_10s,_lease_TTL_is_preserved_after_2_leader_changes (27.07s)