RFR: 8342818: Implement CPU Time Profiling for JFR [v42]

[Johannes Bechberger]

> This is the code for the [JEP draft: CPU Time based profiling for JFR].
> 
> Currently tested using [this test suite](https://github.com/parttimenerd/basic-profiler-tests).

Johannes Bechberger has updated the pull request incrementally with two additional commits since the last revision:

 - Mark queue element as empty to prevent stalling
 - Remove debug output

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Changes:
  - all: https://git.openjdk.org/jdk/pull/20752/files
  - new: https://git.openjdk.org/jdk/pull/20752/files/c65d8704..f1bb87f1

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20752&range=41
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20752&range=40-41

  Stats: 13 lines in 1 file changed: 6 ins; 5 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20752.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20752/head:pull/20752

PR: https://git.openjdk.org/jdk/pull/20752