[jdk20u] RFR: 8302595: use-after-free related to GraphKit::clone_map

[Tobias Hartmann]

Backport of [JDK-8302595](https://bugs.openjdk.java.net/browse/JDK-8302595). Applies cleanly. Approval is pending.

Thanks,
Tobias

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Commit messages:
 - 8302595: use-after-free related to GraphKit::clone_map

Changes: https://git.openjdk.org/jdk20u/pull/27/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk20u&pr=27&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8302595
  Stats: 47 lines in 7 files changed: 40 ins; 0 del; 7 mod
  Patch: https://git.openjdk.org/jdk20u/pull/27.diff
  Fetch: git fetch https://git.openjdk.org/jdk20u.git pull/27/head:pull/27

PR: https://git.openjdk.org/jdk20u/pull/27