RFR: 8345040: Clean up unused variables and code in `generate_native_wrapper`

[Damon Fenacci]

On Tue, 26 Nov 2024 08:16:56 GMT, Qizheng Xing <qxing at openjdk.org> wrote:

> Some of variables and code are related to critical JNI natives feature, which was removed in JDK 18. This patch cleans them up.

Thanks for cleaning up. Looks good to me but could only test x86_64 and aarch64.

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Marked as reviewed by dfenacci (Committer).

PR Review: https://git.openjdk.org/jdk/pull/22384#pullrequestreview-2462201733