WeakLockFreeCache not clean up weak keys when computeIfAbsent

[danielqsj]

Describe the bug
As this PR #5316 described, WeakLockFreeCache.computeIfAbsent() relay on the expungeStaleEntries() to clean up weak keys.
After this PR #5344, It seems WeakLockFreeCache.computeIfAbsent() cannot clean up anymore.

Steps to reproduce

What did you expect to see?

What did you see instead?

What version are you using?
v1.11.0

Environment
Compiler: (e.g., "AdoptOpenJDK 11.0.6")
OS: (e.g., "Ubuntu 20.04")
Runtime (if different from JDK above): (e.g., "Oracle JRE 8u251")
OS (if different from OS compiled on): (e.g., "Windows Server 2019")

Additional context
Add any other context about the problem here.