RFR: 8300658: memory_and_swap_limit() reporting wrong values on systems with swapaccount=0

[Severin Gehwolf]

Please review this change which brings the hotspot code up to date with how the Java metrics behave. On a system where swap accounting is disabled `VM.info` jcmd - for example - no longer reports an unsupported metric, but the memory limit instead as that is actually what is being in place.

I had to update the `TestMemoryWithCgroupV1.java` test as it skipped the swappiness testing based on the now gone output.

Testing:
- [x] Linux container tests on cg1 and cg2 with and without swap accounting.
- [x] New regression test fails on unpatched systems with `swapaccount=0` kernel option. Passes after.
- [ ] GHA (in progress)

Thoughts?

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Commit messages:
 - 8300658: memory_and_swap_limit() reporting wrong values on systems with swapaccount=0

Changes: https://git.openjdk.org/jdk/pull/12262/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=12262&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8300658
  Stats: 54 lines in 5 files changed: 50 ins; 2 del; 2 mod
  Patch: https://git.openjdk.org/jdk/pull/12262.diff
  Fetch: git fetch https://git.openjdk.org/jdk pull/12262/head:pull/12262

PR: https://git.openjdk.org/jdk/pull/12262