[fix][Java Client] Fix thread safety issue of LastCumulativeAck

[BewareMyPower]

Motivation

There were several issues caused by the thread safe issue of
LastCumulativeAck, see:

• Fix NPE when ACK grouping tracker checks duplicated message id #10586
• fix lastCumulativeAck.messageId npe when PersistentAcknowledgmentsGroupingTracker.flushSync #12343

The root cause is that LastCumulativeAck could be accessed by
different threads, especially in flushAsync method. But the fields are
accessed directly and no thread safety can be guaranteed.

In addition, the current LastCumulativeAck class was added in
#8996 to hold two object
references, but this modification is wrong.

Before #8996, there are two CAS operations in doCumulativeAck method
in case it's called concurretly. Though the composite CAS operation is
not atomic.

However, after #8996, only CAS operation was performed but it's compared
with a LastCumulativeAck object, not the two fields (messageId and
bitSetRecyclable).

There is another issue that it uses a flag cumulativeAckFlushRequired
to mark if lastCumulativeAck should flush. However, if flushAsync
was called concurrently, both would send ACK commands to broker.

Modifications

To solve the thread safety issue, this PR move the LastCumulativeAck
out of the PersistentAcknowledgmentsGroupingTracker to disable
directly access to the internal fields. Then, the following synchronized
methods were added to guarantee the thread safety:

• update: Guarantee the safe write operations. It also recycles the
  BitSetRecyclable object before assigning new values and indicates
  itself can be flushed.
• flush: If it can be flushed, return a thread local
  LastCumulativeAck instance that contains the message ID and the bit
  set. The bit set is deep copied to avoid the original reference being
  recycled in another update call.

In addition, since the messageId field is volatile, the getMessageId
method can always retrieve the latest reference.

LastCumulativeAckTest is added to verify the sematics above.

Based on the new design, we can only maintain a LastCumulativeAck
field in PersistentAcknowledgmentsGroupingTracker and call the related
methods in doCumulativeAck and flushAsync. It also fixes the problem
that two concurrent flushAsync calls might send the same ACK command
twice.

Documentation

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[BewareMyPower]

Now all tests passed, PTAL, @lhotari @gaozhangmin @congbobo184 @mattisonchao @Technoboy- @codelipenghui

[Demogorgon314]

LGTM. Just left two minor comments.

[BewareMyPower]

I've updated this PR with a refactored change and the PR description has also been updated, PTAL again @Demogorgon314 @congbobo184

[congbobo184]

Nice work!