RFR: 8329998: Remove double initialization for parts of small TypeArrays in ZObjArrayAllocator [v2]

[Axel Boldt-Christmas]

On Wed, 15 May 2024 06:22:33 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> [JDK-8139457](https://bugs.openjdk.org/browse/JDK-8139457) introduced non-word aligned payloads for TypeArrays. This required adaptation in `ZObjArrayAllocator` segmented array allocator. But the implementation does this adaptation even when the size is small enough and dispatches the allocation to `ObjArrayAllocator`, which already handles clearing this memory.
>> 
>> Instead move the initialization of any unaligned payload start to after the segmented allocation decision.
>
> Axel Boldt-Christmas has updated the pull request with a new target base due to a merge or a rebase. The incremental webrev excludes the unrelated changes brought in by the merge/rebase. The pull request contains two additional commits since the last revision:
> 
>  - Merge remote-tracking branch 'upstream_jdk/master' into JDK-8329998
>  - 8329998: Remove double initialization for parts of small TypeArrays in ZObjArrayAllocator

Thanks for the reviews. Reran testing after merge.

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PR Comment: https://git.openjdk.org/jdk/pull/18721#issuecomment-2114308395