RFR: 8335904: Fix invalid comment in ShenandoahLock

[Xiaolong Peng]

Hi all,
   This PR is to fix an invalid comment in ShenandoahLock I introduced in https://github.com/openjdk/jdk/pull/19570/files#r1668249587, thank you turbanoff@ for catching this, it is easy to miss since the PR had been closed.
    This PR should be trivial. 

Best,
Xiaolong.

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Commit messages:
 - 8335904: Fix invalid comment in ShenandoahLock

Changes: https://git.openjdk.org/jdk/pull/20079/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=20079&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8335904
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/20079.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/20079/head:pull/20079

PR: https://git.openjdk.org/jdk/pull/20079