RFR: JDK-8324637: get_total_or_available_swap_space_size no support on AIX

[Matthias Baesken]

The get_total_or_available_swap_space_size coding misses AIX support, we only return 0. This should be enhanced.
The perfstat API can be used, see https://www.ibm.com/docs/pt/aix/7.2?topic=interfaces-perfstat-memory-total-interface .

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Commit messages:
 - JDK-8324637

Changes: https://git.openjdk.org/jdk/pull/17569/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17569&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8324637
  Stats: 7 lines in 1 file changed: 6 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/17569.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17569/head:pull/17569

PR: https://git.openjdk.org/jdk/pull/17569