RFR: Implement JEP 509: JFR CPU-Time Profiling [v45]

[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).
> 
> A version based on the cooperative sampling JEP can be found [here](https://github.com/parttimenerd/jdk/tree/parttimenerd_cooperative_cpu_time_sampler).

Johannes Bechberger has updated the pull request incrementally with one additional commit since the last revision:

  Remove assertions

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/20752/files
  - new: https://git.openjdk.org/jdk/pull/20752/files/9ffe6232..eb3ab54e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=20752&range=44
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=20752&range=43-44

  Stats: 4 lines in 4 files changed: 0 ins; 3 del; 1 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