RFR: 8315149: Add hsperf counters for CPU time of internal GC threads [v51]

[Jonathan Joo]

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

Jonathan Joo has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 56 commits:

 - Merge branch 'openjdk:master' into master
 - remove whitespace
 - Change APIs to be all-static, address other comments
 - Fix namespace issues (2)
   
   Co-authored-by: Stefan Johansson <54407259+kstefanj at users.noreply.github.com>
 - Fix namespace issues
   
   Co-authored-by: Stefan Johansson <54407259+kstefanj at users.noreply.github.com>
 - Cleanup and address comments
 - Update memory tracking type for CPUTimeCounters
 - Fix assertion logic
 - Address comments and refactor TTTC class for simplification
 - Fix whitespace
 - ... and 46 more: https://git.openjdk.org/jdk/compare/940f67c1...63adf78c

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Changes: https://git.openjdk.org/jdk/pull/15082/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=15082&range=50
  Stats: 437 lines in 19 files changed: 432 ins; 4 del; 1 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