RFR: 8355472: Clean up x86 nativeInst after 32-bit x86 removal [v2]

[Aleksey Shipilev]

On Mon, 28 Apr 2025 12:15:00 GMT, Manuel Hässig <duke at openjdk.org> wrote:

>> This PR cleans up code 32-bit x86 code in `nativeInst_x86.*` files.
>> 
>> Testing:
>>  - [x] tier1 through tier4 on x86 plus Oracle internal testing
>
> Manuel Hässig has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Apply readability suggestion
>   
>   Co-authored-by: Aleksey Shipilëv <shipilev at amazon.de>

Ship it.

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Marked as reviewed by shade (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/24911#pullrequestreview-2799265785