RFR: 8367240: Parallel: Refactor PSScavengeCLDClosure

Tue Sep 9 09:06:57 UTC 2025

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

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Commit messages:
 - pgc-cld

Changes: https://git.openjdk.org/jdk/pull/27165/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=27165&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8367240
  Stats: 68 lines in 1 file changed: 25 ins; 36 del; 7 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