tests: stabilize flaky tests in CI

[tzssangglass]

tests: fix flaky tests in CI

This PR fixes the flaky tests that keep showing up in the CI matrix, with root-cause analysis and local reproduction for each.

t/014-bugs.t, t/058-tcp-socket.t — resolver fails on "localhost"

Symptom: localhost could not be resolved (3: Host not found).

Root cause: public recursive resolvers (8.8.8.8 et al) no longer answer A queries for localhost. — RFC 6761 special-use handling pushes that resolution back to stub resolvers (/etc/hosts), but nginx's resolver directive queries the recursive server directly.

Fix: resolve sslip.io (answerable by public resolvers) instead of localhost.

t/189-http2-subreq-error-wakeup.t — file dies with "IPC::Run: timeout on timer" (exit 29)

Evidence: job 101756976592

Root cause: test-nginx arms IPC::Run::timeout() with the exact same value it passes to curl's --max-time, and the IPC::Run timer checks integer-second time() with a 1s fudge (IPC/Run/Timer.pm: end_time = start_time + interval + 1), while curl's clock starts a few milliseconds later (after fork+exec). When curl's launch phase crosses a whole-second boundary — easy on a loaded runner — curl's deadline lands after the harness timer's end_time, so the harness kills curl before its own --max-time fires and croaks, aborting the whole test file (Test::Builder exits with the failed-subtest count, e.g. 29) and leaving --- shutdown_error_log checks to fail spuriously.

Fix: --- curl_options: --max-time=0.9 in the three timeout blocks. curl_options is appended after the scaffold's own --max-time, so curl honors the later, smaller value and always self-expires strictly before the harness timer — the race window disappears. A general fix for test-nginx itself (give IPC::Run::timeout slack over --max-time) will be submitted upstream separately.

t/024-access/on-abort.t TEST 7 — "callback done: +OK" missing

Evidence: job 101756976782

Root cause: the error.log check is one-shot (no polling) and --- wait: 0.2 was the entire budget for abort detection plus the on_abort callback's cosocket roundtrip to redis (~0.22s). On loaded runners this window is regularly blown (locally: a 220ms redis reply still passes, 260ms reliably fails).

Fix: bump --- wait to 1s.

t/128-duplex-tcp-socket.t TEST 4 — tcp_query truncated (7/10 of 11 bytes)

Evidence: job 102101640297, job 102101640217

Root cause: the test sends flush_all\r\n one byte at a time (1ms sleeps); the mock TCP server flushes the received query to tcp_query_file after every recv (atomic rename), and the test side reads the file exactly once after --- wait: 0.05. On a loaded runner the forked mock server gets starved between recvs, so the check samples the file while it still holds a 7- or 10-byte prefix (got 'flush_a', expected 11 bytes).

Fix: bump --- wait to 0.5s so the mock server can drain the kernel buffer.

Known remaining flake (not addressed here)

t/109-timer-hup.t TEST 3 occasionally flips both timer assertions when the HUP reload is slow enough that the old worker's 3s timer expires normally (prematurely expired: false) instead of being aborted. This is a HUP-timing assumption baked into the test, orthogonal to the fixes above; keeping it under observation for now.

I hereby granted the copyright of the changes in this pull request
to the authors of this lua-nginx-module project.

[tzssangglass]

Lint PR should be fixed by：#2522

[tzssangglass]

@zhuizhuhaomeng PTAL