[lilliput-jdk21u:lilliput] RFR: 8315046: [Lilliput/JDK21] Cherry-pick: 8305896: Alternative full GC forwarding [v2]

[Aleksey Shipilev]

On Tue, 12 Sep 2023 10:47:17 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

>> Let's cherry-pick the alternative full GC forwarding PR in its current state into Lilliput-21.
>> I needed to make some adjustments because PreservedMarks stuff has been refactored between 21 and 22.
>> 
>> Testing:
>> - [ ] hotspot_gc +UseAltGCForwarding
>> - [ ] hotspot_gc -UseAltGCForwarding
>
> Roman Kennke has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:
> 
>  - Merge branch 'lilliput' into JDK-8315046
>  - 8315046: [Lilliput/JDK21] Cherry-pick: 8305896: Alternative full GC forwarding

Marked as reviewed by shade (Reviewer).

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PR Review: https://git.openjdk.org/lilliput-jdk21u/pull/3#pullrequestreview-1621959457