RFR: 8375364: Some jpackage signing tests fail after JDK-8375240

[Alexey Semenyuk]

Fix a regression from the JDK-8375240

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Commit messages:
 - 8375364: Some jpackage signing tests fail after JDK-8375240

Changes: https://git.openjdk.org/jdk/pull/29241/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=29241&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8375364
  Stats: 1 line in 1 file changed: 0 ins; 0 del; 1 mod
  Patch: https://git.openjdk.org/jdk/pull/29241.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/29241/head:pull/29241

PR: https://git.openjdk.org/jdk/pull/29241