RFR: 8351444: Shenandoah: Class Unloading may encounter recycled oops [v3]

[William Kemper]

> Not clean, but not hard to resolve.

William Kemper has updated the pull request incrementally with one additional commit since the last revision:

  Fix build

-------------

Changes:
  - all: https://git.openjdk.org/shenandoah-jdk21u/pull/177/files
  - new: https://git.openjdk.org/shenandoah-jdk21u/pull/177/files/ee804750..511c9805

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=177&range=02
 - incr: https://webrevs.openjdk.org/?repo=shenandoah-jdk21u&pr=177&range=01-02

  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/shenandoah-jdk21u/pull/177.diff
  Fetch: git fetch https://git.openjdk.org/shenandoah-jdk21u.git pull/177/head:pull/177

PR: https://git.openjdk.org/shenandoah-jdk21u/pull/177