RFR: 7903984: Inline upcallHandle method to reduce shared code across multiple generations [v4]

[Nizar Benalla]

On Fri, 11 Apr 2025 08:39:28 GMT, Nizar Benalla <nbenalla at openjdk.org> wrote:

>> Please review this patch to inline the upcallHandle method, reducing the amount of shared items across multiple jextract generations.
>> 
>> Edit: all tests pass in CI, GitHub failure is unrelated 
>> 
>> TIA
>
> Nizar Benalla has updated the pull request incrementally with one additional commit since the last revision:
> 
>   make utility classes final with a private constructor

Based on some offline discussions, I made the function classes final with a private constructor.

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PR Comment: https://git.openjdk.org/jextract/pull/279#issuecomment-2796241055