buf_pool_zip_hash mutex declared with buf_pool_zip_free key

A regression in 5.7 port from 5.6. Fixed by upstream 8.0.14:

commit 5ce335439e2fe2bda98c2292116f41959cfda8da
Author: Rahul Agarkar <rahul.agarkar@oracle.com>
Date: Wed Sep 26 10:12:25 2018 +0530

Bug#28556539 LOCK_ORDER: CYCLE INVOLVING BUF_POOL_FREE_LIST_MUTEX AND
BUF_POOL_ZIP_FREE_MUTEX

Problem:
The LOCK_ORDER tool reports a cycle in innodb mutex locks because of
incorrectly mapped key while creating a mutex. Because of this incorrect
mapping, the tool assumes there is a cycle between two mutexes
potentially leading to a deadlock.

Solution:
Replaced the incorrect key with the correct one

RB: 20610
Reviewed By: Debarun Banerjee (debarun.banerjee@oracle.com)