RFR: 8315149: Add hsperf counters for CPU time of internal GC threads [v9]

[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 incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains ten additional commits since the last revision:

 - Merge branch 'openjdk:master' into master
 - Fix includes
 - Move ThreadTotalCPUTimeClosure to thread.hpp
 - Properly initialize concurrent dedup thread counter
 - rename counters to be *.cpu_time
 - address partial comments from Volker and Man
 - address remainder of dholmes' comments
 - address dholmes@ comments
 - Add hsperf counters for CPU time of JVM internal threads

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Changes:
  - all: https://git.openjdk.org/jdk/pull/15082/files
  - new: https://git.openjdk.org/jdk/pull/15082/files/2f44b814..27c45a3c

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=15082&range=08
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=15082&range=07-08

  Stats: 76507 lines in 2417 files changed: 43696 ins; 16906 del; 15905 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