RFR: 8325821: [REDO] use "dmb.ishst+dmb.ishld" for release barrier [v6]

[kuaiwei]

On Wed, 29 May 2024 11:07:25 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> I checked code again. They will be merged if enable AlwaysMergeDMB. So we can skip the check.
>
> Add a comment:
> 
> `// These will be merged if AlwaysMergeDMB is enabled.`

Comment added.

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PR Review Comment: https://git.openjdk.org/jdk/pull/19278#discussion_r1620242166