SSLTest intermittently hanging on CI

The test that hangs is failed login with SSL.System (ssl available). Debug output when it fails:

 → StartupMessage(jimmy,world,Map(client_min_messages -> WARNING, DateStyle -> ISO, MDY, IntervalStyle -> iso_8601, client_encoding -> UTF8))
TLS: wrap result: Status = OK HandshakeStatus = NEED_UNWRAP
bytesConsumed = 0 bytesProduced = 383 sequenceNumber = 0
TLS: unwrapHandshake result: Status = OK HandshakeStatus = NEED_TASK
bytesConsumed = 66 bytesProduced = 0
TLS: unwrapHandshake result: Status = OK HandshakeStatus = NEED_TASK
bytesConsumed = 695 bytesProduced = 0
 → Terminate

Example: https://github.com/typelevel/skunk/actions/runs/4773385330/jobs/8486427544#step:13:510

When the test passes, output looks like this:

TLS: wrap result: Status = OK HandshakeStatus = NEED_UNWRAP
bytesConsumed = 0 bytesProduced = 383 sequenceNumber = 0
 → StartupMessage(jimmy,world,Map(client_min_messages -> WARNING, DateStyle -> ISO, MDY, IntervalStyle -> iso_8601, client_encoding -> UTF8))
TLS: unwrapHandshake result: Status = OK HandshakeStatus = NEED_TASK
bytesConsumed = 66 bytesProduced = 0
TLS: unwrapHandshake result: Status = OK HandshakeStatus = NEED_TASK
bytesConsumed = 695 bytesProduced = 0
TLS: wrap result: Status = CLOSED HandshakeStatus = NOT_HANDSHAKING
bytesConsumed = 0 bytesProduced = 7 sequenceNumber = 1
 ← PKIX path building failed: sun.security.provider.certpath.SunCertPathBuilderException: unable to find valid certification path to requested target

Start with the failed login with SSL.System (ssl available) test and compare its passing and hanging CI traces, focusing on the TLS handshake and termination sequence. Reproduce it in CI if possible; done means the test no longer hangs intermittently and still reports the expected certificate-path failure when applicable.