[master] RFR: 8306122: [Lilliput] Refactor full GC forwarding

[Aleksey Shipilev]

On Mon, 17 Apr 2023 18:50:16 GMT, Roman Kennke <rkennke at openjdk.org> wrote:

> Current implementation of full-GC/sliding-GC forwarding in Lilliput is problematic:
> - It's scattered and hardwired all over GC implementations
> - It's not switched by UseCompactObjectMonitors
> - The serial compaction in G1 is commented-out and not used, not even under -XX:-UseCompactObjectMonitors
> 
> This change aims to refactor the forwarding code to address these issues.
> 
> It should be functionally equivalent but provides cleaner separation of Lilliput changes. It also cleans up and greatly reduces the upstream diff. The lack of G1 serial compaction with Lilliput enabled will be addressed in a follow-up change.
> 
> Testing:
>  - [x] hotspot_gc
>  - [x] tier1
>  - [ ] tier2

Looks fine for Lilliput

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Marked as reviewed by shade (Committer).

PR Review: https://git.openjdk.org/lilliput/pull/85#pullrequestreview-1389794687