KAFKA-9996: Upgrade zookeeper to 3.5.8 (#8674)
KAFKA-9996: Upgrade zookeeper to 3.5.8 (#8674)

It fixes 30 issues, including third party CVE fixes, several leader-election
related fixes and a compatibility issue with applications built against earlier
3.5 client libraries (by restoring a few non public APIs).

See ZooKeeper 3.5.8 Release Notes for details: https://zookeeper.apache.org/doc/r3.5.8/releasenotes.html

Reviewers: Manikumar Reddy <b4e28923adb1b52fe4083653515cffefae5e9b1d@confluent.io>
guozhangwang/kafka,guozhangwang/kafka,Chasego/kafka,Chasego/kafka,TiVo/kafka,apache/kafka,lindong28/kafka,TiVo/kafka,TiVo/kafka,lindong28/kafka,apache/kafka,guozhangwang/kafka,lindong28/kafka,Chasego/kafka,Chasego/kafka,TiVo/kafka,apache/kafka,apache/kafka,guozhangwang/kafka,lindong28/kafka