RFR: 8359110: Log accumulated GC and process CPU time upon VM exit [v14]

[Jonas Norlinder]

> Add support to log CPU cost for GC during VM exit with `-Xlog:gc+cpu`.
> 
> 
> [1.563s][info][gc,cpu] GC CPU usage: 42.26%

Jonas Norlinder has updated the pull request incrementally with one additional commit since the last revision:

  Change output per discussion

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Changes:
  - all: https://git.openjdk.org/jdk/pull/25779/files
  - new: https://git.openjdk.org/jdk/pull/25779/files/38841dc9..3104ff6a

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=25779&range=13
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=25779&range=12-13

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/25779.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25779/head:pull/25779

PR: https://git.openjdk.org/jdk/pull/25779