RFR: 8337679: Memset warning in src/hotspot/share/adlc/adlArena.cpp

[Yagmur Eren]

The purpose of this `memset` was to overwrite memory with garbage data before freeing it, helping detect bugs where the freed memory is accessed afterward. Therefore, removing it will no impact on functionality. Or it could be zapped with `memset_s` but zapping seems negligible in this case. It passes tier1 tests. See [JDK-8337679](https://bugs.openjdk.org/browse/JDK-8337679).

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Commit messages:
 - 8337679: Memset warning in src/hotspot/share/adlc/adlArena.cpp

Changes: https://git.openjdk.org/jdk/pull/21200/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21200&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8337679
  Stats: 2 lines in 1 file changed: 0 ins; 2 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/21200.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21200/head:pull/21200

PR: https://git.openjdk.org/jdk/pull/21200