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

[Jie Fu]

On Fri, 21 Oct 2022 04:31:09 GMT, Vladimir Kozlov <kvn at openjdk.org> wrote:

> I can't comment on change. I assume it is copy from 64-bit code. 

Yes, it was copied 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.

Sounds good to me.
How about adding the vector api tests in GHA in a separate PR?
Thanks.

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