RFR: 8333871: Check sysinfo return values [v6]

[David Holmes]

On Thu, 20 Nov 2025 08:27:43 GMT, Matthias Baesken <mbaesken at openjdk.org> wrote:

>> In the review of [JDK-8333522](https://bugs.openjdk.org/browse/JDK-8333522) it has been discussed that we might run into issues because of failing sysinfo.
>> However we miss checking the return values at some places, this might need adjustment.
>
> Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:
> 
>   Better assert messages

LGTM. Thanks

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Marked as reviewed by dholmes (Reviewer).

PR Review: https://git.openjdk.org/jdk/pull/28317#pullrequestreview-3490151681