RFR: 8320112 GenShen: Improve end of process report [v2]

[William Kemper]

On Tue, 14 Nov 2023 23:14:48 GMT, William Kemper <wkemper at openjdk.org> wrote:

>> When Shenandoah is shutdown, it logs a summary of its activity over the life of the process. This change adds percentages to the breakdown of the types and counts of cycles that executed. It also simplifies some of the logic around recording the various outcomes.
>
> William Kemper has updated the pull request incrementally with two additional commits since the last revision:
> 
>  - Reduce visibility of new methods
>  - Fix accidental whitespace change

src/hotspot/share/gc/shenandoah/shenandoahControlThread.cpp line 805:

> 803:     assert(_degen_generation->is_young(), "Expected degenerated young cycle, if not global.");
> 804:     ShenandoahOldGeneration* old = heap->old_generation();
> 805:     if (old->state() == ShenandoahOldGeneration::BOOTSTRAPPING) {

An assert has been added in `ShenandoahFullGC` to be certain the old generation is put in the `WAITING_FOR_BOOTSTRAP` state after a Full GC>

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/357#discussion_r1394614574