RFR: 8340137: GenShen: Reset mark bitmaps when a region is recycled

[Kelvin Nilsen]

On Fri, 13 Sep 2024 17:53:00 GMT, William Kemper <wkemper at openjdk.org> wrote:

> Historically, the concurrent reset phase has reset bitmaps for _all_ committed regions. In the generational mode, however, we wish to reset bitmaps for only the generation being collected. This action was recently made to exclude free regions. This broke an assert for regions that became committed (active) after concurrent reset. To address this, we can reset bitmaps for a region when it is recycled (resets still happen for active regions during concurrent reset).
> 
> ## Testing
> GHA, internal pipelines

Marked as reviewed by kdnilsen (Committer).

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PR Review: https://git.openjdk.org/shenandoah/pull/500#pullrequestreview-2303929357