RFR: 8315149: Add hsperf counters for CPU time of internal GC threads [v39]

[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:

  Refactor changes to counters, successful build

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15082/files
  - new: https://git.openjdk.org/jdk/pull/15082/files/ac780c5e..22ccb909

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15082&range=38
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15082&range=37-38

  Stats: 149 lines in 16 files changed: 26 ins; 112 del; 11 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