RFR: 8322057: Memory leaks in creating jfr symbol array

[Zhengyu Gu]

A small fix to avoid memory leak when temporary c string is allocated in c heap.

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Commit messages:
 - 8322057: Memory leaks in creating jfr symbol array

Changes: https://git.openjdk.org/jdk/pull/17099/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=17099&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8322057
  Stats: 8 lines in 2 files changed: 8 ins; 0 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/17099.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/17099/head:pull/17099

PR: https://git.openjdk.org/jdk/pull/17099