Two ecstore test groups pass in isolation but flake under the full parallel
nextest suite, producing CI noise on every in-flight PR (backlog #937):
- store::bucket::tests::bucket_delete_* race make_bucket into
InsufficientWriteQuorum because they share global disk-registry/lock-client
state with other concurrently running tests.
- bucket_lifecycle_ops::tests::concurrent_resend_same_part_commits_one_generation
exceeds its already-maxed 60s lock-acquire deadline only when the suite
saturates disk I/O.
serial_test's #[serial] does not serialize these across nextest's per-test
process boundary. Add a nextest test-group (max-threads = 1) that matches both
groups so they run serialized, removing the load-induced flake. No test or
production code changes; long-term global-singleton isolation is tracked
separately.
Co-authored-by: heihutu <heihutu@gmail.com>
houseme