[jdk23u] RFR: 8338389: [JFR] Long strings should be added to the string pool

[Joakim Nordström]

Backport of fix to pool all longer strings in JFR events.

-------------

Commit messages:
 - Backport d5c6158cedfd96a9f97d83355b10730b81274648

Changes: https://git.openjdk.org/jdk23u/pull/97/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk23u&pr=97&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8338389
  Stats: 119 lines in 2 files changed: 116 ins; 0 del; 3 mod
  Patch: https://git.openjdk.org/jdk23u/pull/97.diff
  Fetch: git fetch https://git.openjdk.org/jdk23u.git pull/97/head:pull/97

PR: https://git.openjdk.org/jdk23u/pull/97