[jdk21u] RFR: 8310239: Add missing cross modifying fence in nmethod entry barriers

[Erik Österlund]

8310239: Add missing cross modifying fence in nmethod entry barriers

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Commit messages:
 - Backport 4679e9aa00c098cff715fb4deeb4d736e1063571

Changes: https://git.openjdk.org/jdk21u/pull/359/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk21u&pr=359&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8310239
  Stats: 10 lines in 1 file changed: 9 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk21u/pull/359.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u.git pull/359/head:pull/359

PR: https://git.openjdk.org/jdk21u/pull/359