RFR: 8327000: GenShen: Integrate updated Shenandoah implementation of FreeSet into GenShen

[Y. Srinivas Ramakrishna]

On Thu, 27 Jun 2024 20:38:32 GMT, Kelvin Nilsen <kdnilsen at openjdk.org> wrote:

> This pull request contains a backport of commit 9d2712dd from the openjdk/shenandoah repository.
> 
> The commit being backported was authored by Kelvin Nilsen on 26 Jun 2024 and was reviewed by William Kemper and Y. Srinivas Ramakrishna.

LGTM.

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Marked as reviewed by ysr (Committer).

PR Review: https://git.openjdk.org/shenandoah-jdk21u/pull/62#pullrequestreview-2164045317