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

[Vladimir Kozlov]

On Fri, 21 Oct 2022 03:55:50 GMT, Jie Fu <jiefu at openjdk.org> wrote:

> Hi all,
> 
> Many vector api tests fail on x86_32 after JDK-8293409 due to computing incorrect results.
> The reason is that `generate_iota_indices` was updated only for x86_64 in JDK-8293409.
> So let's fix it for x86_32.
> 
> Testing:
>   - vector api tests on x86_32, all passed
> 
> Thanks.
> Best regards,
> Jie

I can't comment on change. I assume it is copy from 64-bit code.
But I am starting to concern about Vector API changes causing issues which were not caught during pre-integration testing.
Unfortunately these tests run in [jdk_tier3](https://github.com/openjdk/jdk/blob/master/test/jdk/TEST.groups#L73) only. And as result are not part of GitHub Action testing. And in Oracle we don't test 32-bit.

May I suggest in addition to currently run `tier1_part*` in GHA add `jdk_vector` to it.
I looked on our internal testing times and all 3 `tier1_part*` and `jdk_vector` took about 5 min to run.

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