test: CI test with DNS resolved feature is flaky

Nevertheless the PR only be modified the README.md doc, the CI is failed which completely unrelated to the changes.
https://github.com/openresty/lua-nginx-module/pull/2492

https://github.com/openresty/lua-nginx-module/actions/runs/23824388575/job/69443965578?pr=2492

#   Failed test 't/058-tcp-socket.t TEST 50: cosocket resolving aborted by coroutine yielding failures (require) - pattern "resolve name done" should match a line in error.log (req 0)'

058-tcp-socket.t is used an external DNS server which cause occasionally a communication failure
https://github.com/openresty/lua-nginx-module/blob/c81c9517034aa7868fc333df5d53af9c860056eb/t/058-tcp-socket.t#L13

Indeed it would be highly successful to be extended wait time but it cannot be solved fundamentally.
https://github.com/openresty/lua-nginx-module/blob/c81c9517034aa7868fc333df5d53af9c860056eb/t/058-tcp-socket.t#L3087

How can we solved it?

Start with t/058-tcp-socket.t, especially the external DNS setup near line 13 and the wait-time logic near line 3087. Reproduce the CI failure from the linked run and trace test 50's expectation for "resolve name done" in error.log; done means the test no longer fails intermittently when DNS communication is delayed or unavailable.