RFR: 8371284: GenShen: Avoid unnecessary card marking [v3]

[Aleksey Shipilev]

On Mon, 10 Nov 2025 23:33:21 GMT, Nityanand Rai <duke at openjdk.org> wrote:

>> Exclude young-young, old-old and honor UseCondCardMark in dirty card marking.
>
> Nityanand Rai has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Apply suggestions from code review
>   
>   Co-authored-by: Aleksey Shipilëv <shipilev at amazon.de>

Looks fine. How's performance? I suppose this is a frequent path, and `is_in_young` checks are not necessarily free.

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PR Review: https://git.openjdk.org/jdk/pull/28204#pullrequestreview-3447143143