RFR: 7904027: JOL: Add test cases for ZGC and object alignments [v2]

[Aleksey Shipilev]

On Fri, 6 Jun 2025 16:01:44 GMT, Anton Rybochkin <duke at openjdk.org> wrote:

>> This test reveals incorrect object alignment detection when using generational ZGC which results in high object size reported (512k on aarch64 and 64k otherwise)
>
> Anton Rybochkin has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Fixed default alignment on 32-bit platforms

jol-core/src/test/java/org/openjdk/jol/vm/HotspotUnsafeTest.java line 23:

> 21:         return alignmentProperty
> 22:                 .map(alignment -> Integer.parseInt(substringAfter(alignment, "=")))
> 23:                 .orElse(Byte.SIZE);

`8`, not `Byte.SIZE`. It is 8-byte (64-bit) alignment. Just a coincidence it is also `8`  :)

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PR Review Comment: https://git.openjdk.org/jol/pull/64#discussion_r2132469851