Summary:
Previously with is_fifo=true we only evict TTL file. Changing it to also evict non-TTL files from oldest to newest, after exhausted TTL files.
Closes https://github.com/facebook/rocksdb/pull/4049

Differential Revision: D8604597

Pulled By: yiwu-arbug

fbshipit-source-id: bc4209ee27c1528ce4b72833e6f1e1bff80082c1