These APIs may return stale or simply incorrect data on shards
other than 0. Newer versions of Scylla are better at maintaining
cross-shard consistency, but we need a simple fix that can be easily and
without risk be backported to older versions; this is the fix.
Add a simple test to check that the `failure_detector/endpoints`
API returns nonzero generation.
Fixes: scylladb/scylladb#15816Closesscylladb/scylladb#15970
* github.com:scylladb/scylladb:
test: rest_api: test that generation is nonzero in `failure_detector/endpoints`
api: failure_detector: fix indentation
api: failure_detector: invoke on shard 0
(cherry picked from commit 9443253f3d)