In d0f5873, we introduced mappings IP–host ID between hint directories and the hint endpoint managers managing them. As a consequence, it may happen that one hint directory stores hints towards multiple nodes at the same time. If any of those nodes leaves the cluster, we should drain the hint directory. However, before these changes that doesn't happen – we only drain it when the node of the same host ID as the hint endpoint manager leaves the cluster.
This PR fixes that draining issue in the pre-host-ID-based hinted handoff. Now no matter which of the nodes corresponding to a hint directory leaves the cluster, the directory will be drained.
We also introduce error injections to be able to test that it indeed happens.
Fixesscylladb/scylladb#18761Closesscylladb/scylladb#18764
* github.com:scylladb/scylladb:
db/hints: Introduce an error injection to test draining
db/hints: Ensure that draining happens
01ff8108c1