RFR: 8344587: Reduce number of "jdk.jpackage.internal" classes used from other packages [v3]

[Alexey Semenyuk]

> Stop using internal AppImageFile, ApplicationLayout, and PackageFile classes in the tests. Replace them with stubs.
> 
> Stop referencing IOUtils class from XmlUtils and PathUtils classes.

Alexey Semenyuk has updated the pull request with a new target base due to a merge or a rebase. The pull request now contains 27 commits:

 - Merge branch 'JDK-8344587' of https://github.com/alexeysemenyukoracle/jdk into JDK-8344587
 - Update test/jdk/tools/jpackage/helpers/jdk/jpackage/test/JPackageCommand.java
   
   Co-authored-by: Andrey Turbanov <turbanoff at gmail.com>
 - Merge branch 'master' into JDK-8344587
 - Minor improvements
 - Make IOUtils class package-private
 - Bugfix & cleanup
 - Merge branch 'master' into SplitIOUtils.DecoupleAppImageFile
 - Bad merge fix
 - Bad merge fix
 - Make AppImageFile and PackageFile classes package-private
 - ... and 17 more: https://git.openjdk.org/jdk/compare/93d4ad4d...4957927a

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Changes: https://git.openjdk.org/jdk/pull/22261/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=22261&range=02
  Stats: 381 lines in 21 files changed: 288 ins; 61 del; 32 mod
  Patch: https://git.openjdk.org/jdk/pull/22261.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/22261/head:pull/22261

PR: https://git.openjdk.org/jdk/pull/22261