RFR: 8261579: AArch64: Support for weaker memory ordering in Atomic [v4]

[Aleksey Shipilev]

On Fri, 25 Jun 2021 15:02:35 GMT, Andrew Haley <aph at openjdk.org> wrote:

>> At present the Atomic operations in HotSpot only support conservative (the very strongest) and relaxed (the weakest) memory ordering.
>> We should add at least seq_cst for LSE. This patch also adds a release-only CAS, needed for Shenandoah.
>
> Andrew Haley has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Sanitize memory order for BSD CAS

Also, if you want all platforms built without errors with GHA, you need to merge in current master.

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PR: https://git.openjdk.java.net/jdk/pull/4597