RFR: 8315149: Add hsperf counters for CPU time of internal GC threads [v38]

[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:

  Attempt to fix duplicate name error in test

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15082/files
  - new: https://git.openjdk.org/jdk/pull/15082/files/9fb36a9e..ac780c5e

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15082&range=37
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15082&range=36-37

  Stats: 8 lines in 1 file changed: 0 ins; 5 del; 3 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