RFR: 8333871: check sysinfo return values

Fri Nov 14 10:40:46 UTC 2025

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.

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Commit messages:
 - JDK-8333871

Changes: https://git.openjdk.org/jdk/pull/28317/files
  Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=28317&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8333871
  Stats: 23 lines in 2 files changed: 15 ins; 0 del; 8 mod
  Patch: https://git.openjdk.org/jdk/pull/28317.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/28317/head:pull/28317

PR: https://git.openjdk.org/jdk/pull/28317