RFR: 8314629: Generational ZGC: Clearing All SoftReferences log line lacks GCId [v3]

[Guoxiong Li]

> Hi all,
> 
> This patch adds the GCId to the log of soft reference policy. I move the related code to the start of the old generational GC which needs  to add a parameter `ZDriverRequest` in the method `ZDriverMajor::collect_old`. An alternative, which doesn't need to add a parameter, is only moving the related code to the start of the major GC, concretely the method `ZDriverMajor::gc`. But considering the references only be cleared in old generational GC, I make such decision. Waiting for your opinion on it.
> 
> Thanks for taking the time to review.
> 
> Best Regards,
> -- Guoxiong

Guoxiong Li has updated the pull request incrementally with one additional commit since the last revision:

  Rename field. Remove comment. Polish.

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Changes:
  - all: https://git.openjdk.org/jdk/pull/17196/files
  - new: https://git.openjdk.org/jdk/pull/17196/files/138c787d..8e383e87

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=17196&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=17196&range=01-02

  Stats: 9 lines in 2 files changed: 2 ins; 4 del; 3 mod
  Patch: https://git.openjdk.org/jdk/pull/17196.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17196/head:pull/17196

PR: https://git.openjdk.org/jdk/pull/17196