Upgrade urgency: SECURITY, contains fixes to security issues.

Security Fixes:

• (CVE-2021-41099) Integer to heap buffer overflow handling certain string commands and network payloads, when proto-max-bulk-len is manually configured to a non-default, very large value [reported by yiyuaner].
• (CVE-2021-32762) Integer to heap buffer overflow issue in redis-cli and redis-sentinel parsing large multi-bulk replies on some older and less common platforms [reported by Microsoft Vulnerability Research].
• (CVE-2021-32687) Integer to heap buffer overflow with intsets, when set-max-intset-entries is manually configured to a non-default, very large value [reported by Pawel Wieczorkiewicz, AWS].
• (CVE-2021-32675) Denial Of Service when processing RESP request payloads with a large number of elements on many connections.
• (CVE-2021-32672) Random heap reading issue with Lua Debugger [reported by Meir Shpilraien].
• (CVE-2021-32628) Integer to heap buffer overflow handling ziplist-encoded data types, when configuring a large, non-default value for hash-max-ziplist-entries, hash-max-ziplist-value, zset-max-ziplist-entries or zset-max-ziplist-value [reported by sundb].
• (CVE-2021-32627) Integer to heap buffer overflow issue with streams, when configuring a non-default, large value for proto-max-bulk-len and client-query-buffer-limit [reported by sundb].
• (CVE-2021-32626) Specially crafted Lua scripts may result with Heap buffer overflow [reported by Meir Shpilraien].

Other bug fixes:

• Fix appendfsync to always guarantee fsync before reply, on MacOS and FreeBSD (kqueue) (#9416)
• Fix the wrong mis-detection of sync_file_range system call, affecting performance (#9371)
• Fix replication issues when repl-diskless-load is used (#9280)