RFR: Fix satb barrier for object array copy [v2]

[Aleksey Shipilev]

On Thu, 30 Mar 2023 23:32:31 GMT, Kelvin Nilsen <kdnilsen at openjdk.org> wrote:

>> The satb barrier for overwritten arrays residing in old-gen must be unconditional during young GC.
>> 
>> During old GC, the satb barrier is only needed for overwritten old-gen arrays if the array is below TAMS within its old-gen region.
>
> Kelvin Nilsen has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fix typo in comment

I have no further comments on top of what @earthling-amzn already suggested. I'll stamp the approval once those changes are in. Maybe merge from master to get cleaner PR.

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PR Review: https://git.openjdk.org/shenandoah/pull/237#pullrequestreview-1366476049