RFR: JDK-8320168: handle setsocktopt return values [v2]

[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.

Matthias Baesken has updated the pull request incrementally with one additional commit since the last revision:

  adjust comment in Net.c

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Changes:
  - all: https://git.openjdk.org/jdk/pull/16684/files
  - new: https://git.openjdk.org/jdk/pull/16684/files/f5cf86db..687ec6e3

Webrevs:
 - full: https://webrevs.openjdk.org/?repo=jdk&pr=16684&range=01
 - incr: https://webrevs.openjdk.org/?repo=jdk&pr=16684&range=00-01

  Stats: 3 lines in 1 file changed: 1 ins; 0 del; 2 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