[jdk20u] RFR: 8307346: Add missing gc+phases logging for ObjectCount(AfterGC) JFR event collection code

Tue May 16 09:21:53 UTC 2023

Hi all,

This pull request contains a clean backport of commit [3f1927a7](https://github.com/openjdk/jdk/commit/3f1927a7f3a2914402a25335c47a5a8bdd5511a6) from the [openjdk/jdk](https://git.openjdk.org/jdk) repository.

The commit being backported was authored by Oli Gillespie on 4 May 2023 and was reviewed by Thomas Schatzl, Aleksey Shipilev and Albert Mingkun Yang.

Thanks!

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Commit messages:
 - Backport 3f1927a7f3a2914402a25335c47a5a8bdd5511a6

Changes: https://git.openjdk.org/jdk20u/pull/79/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk20u&pr=79&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8307346
  Stats: 12 lines in 3 files changed: 9 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk20u/pull/79.diff
  Fetch: git fetch https://git.openjdk.org/jdk20u.git pull/79/head:pull/79

PR: https://git.openjdk.org/jdk20u/pull/79