lsa: Avoid excessive eviction if region is not compactible
lsa: Avoid excessive eviction if region is not compactible

Introduced in d72b91053b7dff849eac7321e1cfc787cefe65f4.

If region was not compactible, for example because it has dense
segments, we would keep evicting even though the target for reclaimed
segments was met. In the worst case we may have to evict whole cache.

Refs #9038 (unlikely to be the cause though)
Message-Id: <b66d03ad9f466c4375dfa870f91a303762ed5dbd@scylladb.com>

scylladb/scylla,scylladb/scylla,scylladb/scylla,scylladb/scylla