RFR: 8365555: Cleanup redundancies in jpackage implementation

[Alexey Semenyuk]

On Fri, 15 Aug 2025 00:21:49 GMT, Alexander Matveev <almatvee at openjdk.org> wrote:

>> - Remove AppImageDesc class. It was supposed to bind an AppImageLayout instance with a root directory, but since AppImageLayout has `rootDirectory()` method it is redundant.
>>  - Remove redundant `Package.packageLayout()` and `Package.asPackageApplicationLayout()` methods from the model, 
>>  - Add tests for PackagingPipeline class.
>>  - Move JUnitAdapter.java from "/test/jdk/tools/jpackage/helpers-test" to "/test/jdk/tools/jpackage/junit/tools" directory, support running platform-specific JUnit tests.
>>  - Enhance AppImageLayout class, add unit tests for derived MacApplicationLayout and LinuxApplicationLayout classes.
>>  - Add tests for BuildEnv class.
>
> test/jdk/tools/jpackage/junit/share/jdk.jpackage/jdk/jpackage/internal/PackagingPipelineTest.java line 189:
> 
>> 187: 
>> 188:         assertEquals(expected, actual);
>> 189:         System.out.println(String.format("testCreatePackage:\n---\n%s\n---", actual));
> 
> Looks like debug `println`.

It is on purpose to get an idea of what the test with the given parameter value is doing

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PR Review Comment: https://git.openjdk.org/jdk/pull/26778#discussion_r2278257978