RFR: 8342681: TestLoadBypassesNullCheck.java fails improperly specified VM option

[SendaoYan]

Hi all,
Newly added test `gc/shenandoah/compiler/TestLoadBypassesNullCheck.java` fails `The unlock option must precede 'StressGCM'.` with release jdk build. This PR fix the test bug.
The change has been verified locally with release/fastdebug/slowdebug on linux-x64. Test-fix only, no risk.

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Commit messages:
 - 8342681: TestLoadBypassesNullCheck.java fails improperly specified VM option

Changes: https://git.openjdk.org/jdk/pull/21609/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=21609&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8342681
  Stats: 6 lines in 1 file changed: 2 ins; 0 del; 4 mod
  Patch: https://git.openjdk.org/jdk/pull/21609.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/21609/head:pull/21609

PR: https://git.openjdk.org/jdk/pull/21609