RFR: 8338922: Parallel: Add task queue stats support in full GC

[Zhengyu Gu]

Add capability to print out task queue stats in Parallel Compact GC, like other GCs.

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Commit messages:
 - 8338922: Parallel: Add task queue stats support in full GC

Changes: https://git.openjdk.org/jdk/pull/20694/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20694&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338922
  Stats: 24 lines in 3 files changed: 22 ins; 0 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/20694.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20694/head:pull/20694

PR: https://git.openjdk.org/jdk/pull/20694