[jdk21u-dev] RFR: 8343100: Consolidate EmptyFolderTest and EmptyFolderPackageTest jpackage tests into single java file

[Goetz Lindenmaier]

I backport this to keep testing up to date.

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Commit messages:
 - Backport 00fe9f7bdfd245791bca6b5b1b2d0a98d41af221

Changes: https://git.openjdk.org/jdk21u-dev/pull/1218/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk21u-dev&pr=1218&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8343100
  Stats: 254 lines in 5 files changed: 87 ins; 146 del; 21 mod
  Patch: https://git.openjdk.org/jdk21u-dev/pull/1218.diff
  Fetch: git fetch https://git.openjdk.org/jdk21u-dev.git pull/1218/head:pull/1218

PR: https://git.openjdk.org/jdk21u-dev/pull/1218