RFR: 8371284: GenShen: Avoid unnecessary card marking [v5]

[Aleksey Shipilev]

On Wed, 19 Nov 2025 23:31:41 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:
> 
>   hardening of comments
>   
>   remove unintended files

I am good with comments as they are. Thanks.

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Marked as reviewed by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28204#pullrequestreview-3563550852