RFR: 8295762: [Vector API] Update generate_iota_indices for x86_32 after JDK-8293409

[Jie Fu]

On Fri, 21 Oct 2022 04:08:46 GMT, Xiaohong Gong <xgong at openjdk.org> wrote:

> Thanks for fixing it @DamonFool ! The change looks good to me!

Thanks @XiaohongGong for your review.

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PR: https://git.openjdk.org/jdk/pull/10807