test_event opens 256 UDP receivers plus a sender on top of the loop's own
descriptors. macOS starts processes with a soft RLIMIT_NOFILE of 256, so
socket() eventually returned -1 and the unchecked descriptor tripped the
bind() assertion when running ctest from a stock terminal (#3058).
Wrap every registered unit test in a small sh launcher that raises the soft
limit to 1024 before exec'ing the binary, and have test_event raise its own
limit as well so it also passes when run directly. Assert on socket()
failures so a limit problem is reported as such instead of as a bind error.
Fixes#3058
Claude-Session: https://claude.ai/code/session_01PSG4XV3jiqitDgdgFSGATx
Max Lv
8773939dce