Add swapped_count field to vm_statistics64 on macOS

[Thomasdezeeuw]

Description

Adds a missing field to vm_statistics64 on macOS

Sources

• https://github.com/apple-oss-distributions/xnu/blob/f6217f891ac0bb64f3d375211650a4c1ff8ca1ea/osfmk/mach/vm_statistics.h#L176

Checklist

• Relevant tests in libc-test/semver have been updated
• No placeholder or unstable values like *LAST or *MAX are
  included (see #3131)
• Tested locally (cd libc-test && cargo test --target mytarget);
  especially relevant for platforms that may not be checked in CI

[tgross35]

Same CI issue as #4925. Unfortunately, this is also a breaking change :( so I'm not sure we can get it into a stable release

[rustbot]

Reminder, once the PR becomes ready for a review, use @rustbot ready.

[Thomasdezeeuw]

Removed the stable nomination, will wait until #4925 is merged to continue with this.