patch 8.3 src to use avx512 cache vars

[henderkes]

What does this PR do?

closes #1111
also closes #1114 , whatever that attempt was
turns out 8.2 had no avx512, 8.3 ran the checks unconditionally.
backported the 8.4 checks into 8.3 here.

Checklist before merging

If your PR involves the changes mentioned below and completed the action, please tick the corresponding option.
If a modification is not involved, please skip it directly.

• If you modified *.php or *.json, run them locally to ensure your changes are valid:
  • composer cs-fix
  • composer analyse
  • composer test
  • bin/spc dev:sort-config
• If it's an extension or dependency update, please ensure the following:
  • Add your test combination to src/globals/test-extensions.php.
  • If adding new or fixing bugs, add commit message containing extension test or test extensions to trigger full test suite.

[henderkes]

https://github.com/static-php/packages/actions/runs/24654914831/job/72085983883