RFR: 8370965: Remove SigningPackageFromTwoStepAppImageTest test

[Alexey Semenyuk]

Remove redundant SigningPackageFromTwoStepAppImageTest test.

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Commit messages:
 - empty
 - SigningPackageFromTwoStepAppImageTest: remove

Changes: https://git.openjdk.org/jdk/pull/28068/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28068&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8370965
  Stats: 195 lines in 1 file changed: 0 ins; 195 del; 0 mod
  Patch: https://git.openjdk.org/jdk/pull/28068.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28068/head:pull/28068

PR: https://git.openjdk.org/jdk/pull/28068