RFR: 8358183: [JVMCI] crash accessing nmethod::jvmci_name in CodeCache::aggregate

[Boris Ulasevich]

Zero out _mutable_data_size, _relocation_size and _metadata_size in purge() so that after purge jvmci_data_size() returns 0 and print_heapinfo() won’t touch an invalid _metadata.

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Commit messages:
 - 8358183: [JVMCI] crash accessing nmethod::jvmci_name in CodeCache::aggregate

Changes: https://git.openjdk.org/jdk/pull/25608/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=25608&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8358183
  Stats: 3 lines in 2 files changed: 3 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/25608.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/25608/head:pull/25608

PR: https://git.openjdk.org/jdk/pull/25608