RFR: Fix satb barrier for object array copy

[William Kemper]

On Wed, 29 Mar 2023 23:54:25 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.

src/hotspot/share/gc/shenandoah/shenandoahBarrierSet.inline.hpp line 446:

> 444:    *
> 445:    * 1. The overwritten array resides in old-gen and it is below TAMS within its old-gen region
> 446:    * 2. Do not call arraycopy_work for any array residing young-gen because young-gen collection is idle at this time

... array residing _in_ young-gen ...

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PR Review Comment: https://git.openjdk.org/shenandoah/pull/237#discussion_r1153875281