RFR: 8347620: Shenandoah: Use 'free' tag for free set related logging

[William Kemper]

Conflicts related to removal of SSIZE_FORMAT macro.

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Commit messages:
 - Backport 9782bfdd27da95c3bab9da6d46d695e717f465d8

Changes: https://git.openjdk.org/shenandoah-jdk21u/pull/159/files
  Webrev: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=159&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8347620
  Stats: 78 lines in 1 file changed: 7 ins; 7 del; 64 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/159.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/159/head:pull/159

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/159