RFR: 8337938: ZUtils::alloc_aligned allocates without reporting to NMT

[Stefan Karlsson]

On Fri, 9 Aug 2024 12:47:18 GMT, Joel Sikström <duke at openjdk.org> wrote:

> Replaces usage of posix_memalign/_aligned_malloc with os::malloc and manual alignment to report memory usage to NMT. Manually aligning the memory makes the returned address unfreeable by malloc (as clarified by the added comment), which is reasonable since the memory used by ZUtils::alloc_aligned is never freed.
> 
> Tested with tiers 1-3.

Looks good.

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Marked as reviewed by stefank (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/20523#pullrequestreview-2230191554