test_ssl: test_connect_ex_error() hangs on "ARM64 macOS 3.x" buildbot

ARM64 macOS 3.x: https://buildbot.python.org/#/builders/725/builds/13430

0:49:10 load avg: 1.78 [4/4/1] test_ssl worker non-zero exit code (Exit code 1)
Re-running test_ssl in verbose mode
test_DER_to_PEM (test.test_ssl.BasicSocketTests.test_DER_to_PEM) ... ok
test_asn1object (test.test_ssl.BasicSocketTests.test_asn1object) ... ok
test_cert_time_to_seconds (test.test_ssl.BasicSocketTests.test_cert_time_to_seconds) ... ok
test_cert_time_to_seconds_locale (test.test_ssl.BasicSocketTests.test_cert_time_to_seconds_locale) ... skipped 'locale-specific month name needs to be different from C locale'
test_cert_time_to_seconds_timezone (test.test_ssl.BasicSocketTests.test_cert_time_to_seconds_timezone) ... ok
test_connect_ex_error (test.test_ssl.BasicSocketTests.test_connect_ex_error) ... Timeout (0:20:00)!
Thread 0x0000000206e4ec40 (most recent call first):
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/ssl.py", line 1440 in _real_connect
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/ssl.py", line 1461 in connect_ex
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/test/test_ssl.py", line 973 in test_connect_ex_error
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/unittest/case.py", line 637 in _callTestMethod
  File "/Users/buildbot/buildarea/3.x.pablogsal-macos-m1.macos-with-brew/build/Lib/unittest/case.py", line 691 in run
...

test.pythoninfo: OpenSSL 3.6.1

platform.platform: macOS-26.2-arm64-arm-64bit-Mach-O

ssl.HAS_SNI: True
ssl.OPENSSL_VERSION: OpenSSL 3.6.1 27 Jan 2026
ssl.OPENSSL_VERSION_INFO: (3, 6, 0, 1, 0)
ssl.OP_ALL: 0x80000050
ssl.OP_NO_TLSv1_1: 0x10000000
ssl.SSLContext.maximum_version: -1
ssl.SSLContext.minimum_version: 771
ssl.SSLContext.options: 2186412112
ssl.SSLContext.protocol: 16
ssl.SSLContext.verify_mode: 2
ssl.default_https_context.maximum_version: -1
ssl.default_https_context.minimum_version: 771
ssl.default_https_context.options: 2186412112
ssl.default_https_context.protocol: 16
ssl.default_https_context.verify_mode: 2
ssl.stdlib_context.maximum_version: -1
ssl.stdlib_context.minimum_version: 771
ssl.stdlib_context.options: 2186412112
ssl.stdlib_context.protocol: 16
ssl.stdlib_context.verify_mode: 0

ARM64 macOS 3.x:

• Latest success: https://buildbot.python.org/#/builders/725/builds/13429
• First error: https://buildbot.python.org/#/builders/725/builds/13430

Lib/test/test_ssl.py の BasicSocketTests.test_connect_ex から始め、報告された呼び出しを Lib/ssl.py の _real_connect と connect_ex まで追跡します。ARM64 macOS 3.x buildbot のコンテキストでテストを再現し、成功したビルドと失敗したビルドを比較して、test_connect_ex_error がハングしなくなり、test_ssl の実行が完了することを確認します。