RFR: 8353578: Refactor existing usage of internal HKDF impl to use the KDF API [v8]

[Kevin Driver]

On Thu, 8 May 2025 21:19:10 GMT, Valerie Peng <valeriep at openjdk.org> wrote:

>> This PR removes the internal JSSE HKDF impl and changes to use the KDF API for the HKDF support from JCA/JCE providers.
>> 
>> This is just code refactoring. Known-answer regression test for the internal JSSE HKDF impl is removed as the test vectors are already covered by the HKDF impl in SunJCE provider.
>> 
>> Thanks in advance for the review~
>
> Valerie Peng has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Address review feedbacks from Brad.

See inline.

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PR Review: https://git.openjdk.org/jdk/pull/24393#pullrequestreview-2834316490