The setting is deprecated so change the code to either use the
native zsock_* API or enable POSIX_API to use the BSD socket API.
Signed-off-by: Jukka Rissanen <jukka.rissanen@nordicsemi.no>
A fair bit of setup / teardown code was being duplicated in many
test cases in the socketpair testsuite.
Take advantage of the `setup()`, `before()`, and `after()`
functions in the new ZTest API.
Signed-off-by: Christopher Friedt <cfriedt@meta.com>