RFR: 8315149: Add hsperf counters for CPU time of internal GC threads [v41]

[Jonathan Joo]

On Sat, 11 Nov 2023 00:23:28 GMT, Jonathan Joo <jjoo at openjdk.org> wrote:

>> 8315149: Add hsperf counters for CPU time of internal GC threads
>
> Jonathan Joo has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Refactor ConcurrentRefine logic
>  - Make CPUTimeCounters a singleton class

Will address the Remark pause update in my next commit!

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PR Comment: https://git.openjdk.org/jdk/pull/15082#issuecomment-1806593319