[jdk18u] RFR: 8283555: G1: Concurrent mark accesses uninitialized BOT of closed archive regions

[Thomas Schatzl]

Please review this backport of [JDK-8283555](https://bugs.openjdk.java.net/browse/JDK-8283555) G1: Concurrent mark accesses uninitialized BOT of closed archive regions which removes a potential crash.

Applies cleanly.

Testing: gha, jdk19 ci

Thanks,
  Thomas

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Commit messages:
 - 8283555: G1: Concurrent mark accesses uninitialized BOT of closed archive regions

Changes: https://git.openjdk.java.net/jdk18u/pull/54/files
 Webrev: https://webrevs.openjdk.java.net/?repo=jdk18u&pr=54&range=00
  Issue: https://bugs.openjdk.java.net/browse/JDK-8283555
  Stats: 10 lines in 1 file changed: 5 ins; 5 del; 0 mod
  Patch: https://git.openjdk.java.net/jdk18u/pull/54.diff
  Fetch: git fetch https://git.openjdk.java.net/jdk18u pull/54/head:pull/54

PR: https://git.openjdk.java.net/jdk18u/pull/54