Revert "Suppress pytest.PytestUnraisableExceptionWarning raised in test cleanup"

This reverts commit e03247a.

Author: webknjaz

pytest.ini

@@ -65,11 +65,6 @@ filterwarnings =
   ignore:unclosed <socket.socket fd=:ResourceWarning
   ignore:unclosed <ssl.SSLSocket fd=:ResourceWarning
 
-  # FIXME: Python 3.13 no longer ignores IOBase errors raised by the close(),
-  # FIXME: which exposed a possible race condition in test_conn test cleanup.
-  # Ref: https://github.com/cherrypy/cheroot/issues/734
-  ignore:Exception ignored in. <function IOBase.__del__:pytest.PytestUnraisableExceptionWarning
-
 junit_duration_report = call
 junit_family = xunit2
 junit_suite_name = cheroot_test_suite