RFR: 8303920: Avoid calling out to python in DataDescriptorSignatureMissing test [v9]

[Iris Clark]

On Mon, 30 Oct 2023 17:48:48 GMT, Eirik Bjorsnos <duke at openjdk.org> wrote:

>> Please review this PR which brings  the DataDescriptorSignatureMissing test back to life.
>> 
>> This test currently calls out to Python to create a test vector ZIP with a Data Descriptor without the recommended but optional signature. The Python dependency has turned out to be very brittle, so the test is currently marked with `@ignore` 
>> 
>> The PR replaces Python callouts with directly creating the test vector ZIP in the test itself. We can then remove the `@ignore`tag and run this useful test automatically.
>
> Eirik Bjorsnos has updated the pull request incrementally with three additional commits since the last revision:
> 
>  - Describe the structure of Data Descriptors using an example
>  - Extend the comment of `makeZipWithSignaturelessDescriptor` with some background info on (signature-less) data descriptors, for the benefit of future maintainers.
>  - Convert test from testng to junit

Marked as reviewed by iris (Reviewer).

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PR Review: https://git.openjdk.org/jdk/pull/12959#pullrequestreview-1713426994