RFR: 8346869: [AIX] Add regression test for handling 4 Byte aligned doubles in structures

[Joachim Kern]

On Sat, 28 Dec 2024 18:43:30 GMT, Martin Doerr <mdoerr at openjdk.org> wrote:

> [JDK-8317545](https://bugs.openjdk.org/browse/JDK-8317545) introduced code for supporting 4 Byte aligned doubles: https://github.com/openjdk/jdk/blob/60e0730a3ba26180d0eb2cd278e389c3e70fec5f/src/java.base/share/classes/jdk/internal/foreign/abi/ppc64/aix/AixPPC64Linker.java#L59
> We should test this case. The new test can serve as an example implementation for handling such structures in Java code such that it works on all platforms including AIX.

C Code LGTM

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Marked as reviewed by jkern (Committer).

PR Review: https://git.openjdk.org/jdk/pull/22889#pullrequestreview-2546739414