RFR: 8317678: Fix up hashCode() for ZipFile.Source.Key [v10]

[Sean Coffey]

On Mon, 23 Oct 2023 13:04:20 GMT, Sean Coffey <coffeys at openjdk.org> wrote:

>> Fix up java.util.zip.ZipFile$Source hashCode() impl so that duplicate Source objects aren't created for the same zip file.
>
> Sean Coffey has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Incorporate test review comments from Jai

meant to add - note that `createZipFile` already prints an error to standard err in the scenario where the zip file can't be opened for modification.

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PR Comment: https://git.openjdk.org/jdk/pull/16115#issuecomment-1775156218