RFR: 8320304: Refactor and simplify monitor deflation functions [v3]

[Stefan Karlsson]

On Mon, 20 Nov 2023 21:20:40 GMT, Stefan Karlsson <stefank at openjdk.org> wrote:

>> Definitely going to have to merge with [JDK-8319137](https://bugs.openjdk.org/browse/JDK-8319137)!!
>
>>The call to log.before_blocked() on L1725 will stop the timer so it will not
> be running during the ThreadBlockInVM.
> The call to log.after_blocked() on L1731 will restart the timer.
> The advantage of having these two calls is that you know how long we spent in ThreadBlockInVM based on the timestamps in the two log mesgs.
> 
> It's unclear to me if you want me to change anything. Patricio pointed out that the pre-existing logs are around the "wrong" part of the code. It's not interesting to log the constructor, but rather the destructor. Alternatively, the code that deletes the monitors.

>Definitely going to have to merge with JDK-8319137!!

Of course. I had hoped that this would be pushed before that change.

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PR Review Comment: https://git.openjdk.org/jdk/pull/16706#discussion_r1399761227