RFR: 8315149: Add hsperf counters for CPU time of internal GC threads [v54]

[Jonathan Joo]

> 8315149: Add hsperf counters for CPU time of internal GC threads

Jonathan Joo has updated the pull request incrementally with one additional commit since the last revision:

  Return after ShouldNotReachHere
  
  Co-authored-by: Stefan Johansson <54407259+kstefanj at users.noreply.github.com>

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15082/files
  - new: https://git.openjdk.org/jdk/pull/15082/files/7e4cdcd3..fcf00cfe

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15082&range=53
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15082&range=52-53

  Stats: 1 line in 1 file changed: 1 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/15082.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/15082/head:pull/15082

PR: https://git.openjdk.org/jdk/pull/15082