RFR: JDK-8320168: handle setsocktopt return values

[Matthias Baesken]

There are a few places in the JDK C coding where the setsocktopt return value is not handled but better should be handled.

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Commit messages:
 - JDK-8320168

Changes: https://git.openjdk.org/jdk/pull/16684/files
 Webrev: https://webrevs.openjdk.org/?repo=jdk&pr=16684&range=00
  Issue: https://bugs.openjdk.org/browse/JDK-8320168
  Stats: 70 lines in 9 files changed: 47 ins; 0 del; 23 mod
  Patch: https://git.openjdk.org/jdk/pull/16684.diff
  Fetch: git fetch https://git.openjdk.org/jdk.git pull/16684/head:pull/16684

PR: https://git.openjdk.org/jdk/pull/16684