[jdk21u] RFR: 8315026: ProcessHandle implementation listing processes on AIX should use getprocs64

[Joachim Kern]

Hi all,
This pull request contains a backport of commit [4d904204](https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgithub.com%2Fopenjdk%2Fjdk%2Fcommit%2F4d9042043ecade75d50c25574a445e6b8ef43618&data=05%7C01%7Cjoachim.kern%40sap.com%7C76faafca39b84ddcf13408dbcbc85c71%7C42f7676cf455423c82f6dc2d99791af7%7C0%7C0%7C638327833624807033%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=v5v6JFt12KN%2Bvs0nb26YpvanyOqgZr3LyE7FBTGio7Y%3D&reserved=0) from the [openjdk/jdk](https://eur03.safelinks.protection.outlook.com/?url=https%3A%2F%2Fgit.openjdk.org%2Fjdk&data=05%7C01%7Cjoachim.kern%40sap.com%7C76faafca39b84ddcf13408dbcbc85c71%7C42f7676cf455423c82f6dc2d99791af7%7C0%7C0%7C638327833624807033%7CUnknown%7CTWFpbGZsb3d8eyJWIjoiMC4wLjAwMDAiLCJQIjoiV2luMzIiLCJBTiI6Ik1haWwiLCJXVCI6Mn0%3D%7C3000%7C%7C%7C&sdata=Gi20yCL7O4TFRsg%2Ble798pmWnMENvuYuTv4OsWA8gGY%3D&reserved=0) repository.
The commit being backported was authored by Joachim Kern on 13 Oct 2023 and was reviewed by Roger Riggs, Thomas Stuefe and Matthias Baesken.
Thanks!

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Commit messages:
 - Backport 4d9042043ecade75d50c25574a445e6b8ef43618

Changes: https://git.openjdk.org/jdk21u/pull/250/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u&pr=250&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8315026
  Stats: 139 lines in 2 files changed: 130 ins; 0 del; 9 mod
  Patch: https://git.openjdk.org/jdk21u/pull/250.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/250/head:pull/250

PR: https://git.openjdk.org/jdk21u/pull/250