RFR: 8369814: G1: Relax card mark and store ordering [v5]

[Albert Mingkun Yang]

On Tue, 14 Oct 2025 12:49:22 GMT, Albert Mingkun Yang <ayang at openjdk.org> wrote:

>> This PR removes the card-mark and store ordering constraint. The first commit changes `card_mark_must_follow_store` to `false` and the second commit removes all uses of `card_mark_must_follow_store`, because both the original method and its override are identical, and no GC have such ordering requirement any more.
>> 
>> Test: tier1-5
>
> Albert Mingkun Yang has updated the pull request incrementally with one additional commit since the last revision:
> 
>   review

Thanks for review.

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PR Comment: https://git.openjdk.org/jdk/pull/27794#issuecomment-3414639309