RFR: 8329994: Zap alignment padding bits for ArrayOops in non-release builds [v2]

[Stefan Johansson]

On Wed, 10 Apr 2024 13:29:15 GMT, Axel Boldt-Christmas <aboldtch at openjdk.org> wrote:

>> In a similar vein to [JDK-8325870](https://bugs.openjdk.org/browse/JDK-8325870). Zap the any alignment padding that may exist between the header and the payload.
>> 
>> Currently this padding only occurs when disabling `UseCompressedClassPointers`. But becomes more relevant with [JDK-8294992](https://bugs.openjdk.org/browse/JDK-8294992).
>
> Axel Boldt-Christmas has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Rename to mem_zap_start_padding

Marked as reviewed by sjohanss (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/18714#pullrequestreview-2130295085