RFR: 8367240: Parallel: Refactor PSScavengeCLDClosure [v3]

[Albert Mingkun Yang]

> Refactor `PSScavengeCLDClosure` and its "enclosing" `PSScavengeFromCLDClosure` so that all CLD logic is encapsulated in the CLD closure, without polluting the oop closure.
> 
> Test: tier1-3

Albert Mingkun Yang 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 four additional commits since the last revision:

 - review
 - Merge branch 'master' into pgc-cld
 - review
 - pgc-cld

-------------

Changes:
  - all: https://git.openjdk.org/jdk/pull/27165/files
  - new: https://git.openjdk.org/jdk/pull/27165/files/33fb3332..836002b8

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=27165&range=02
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=27165&range=01-02

  Stats: 568 lines in 27 files changed: 356 ins; 144 del; 68 mod
  Patch: https://git.openjdk.org/jdk/pull/27165.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/27165/head:pull/27165

PR: https://git.openjdk.org/jdk/pull/27165