[4.1.x] Fixed thread termination in servers.tests.LiveServerPort on Python 3.10.9+, 3.11.1+, and 3.12+.

Class cleanups registered in TestCase subclasses are no longer called
as TestCase.doClassCleanups() only cleans up the particular class, see

c2102136be
Backport of d02a9f0cee84e3d23f676bdf2ab6aadbf4a5bfe8 from main

tests/servers/tests.py

@@ -351,12 +351,15 @@ class LiveServerPort(LiveServerBase):
                 return
             # Unexpected error.
             raise
-        self.assertNotEqual(
-            self.live_server_url,
-            TestCase.live_server_url,
-            f"Acquired duplicate server addresses for server threads: "
-            f"{self.live_server_url}",
-        )
+        try:
+            self.assertNotEqual(
+                self.live_server_url,
+                TestCase.live_server_url,
+                f"Acquired duplicate server addresses for server threads: "
+                f"{self.live_server_url}",
+            )
+        finally:
+            TestCase.doClassCleanups()
 
     def test_specified_port_bind(self):
         """LiveServerTestCase.port customizes the server's port."""
@@ -367,12 +370,15 @@ class LiveServerPort(LiveServerBase):
         TestCase.port = s.getsockname()[1]
         s.close()
         TestCase._start_server_thread()
-        self.assertEqual(
-            TestCase.port,
-            TestCase.server_thread.port,
-            f"Did not use specified port for LiveServerTestCase thread: "
-            f"{TestCase.port}",
-        )
+        try:
+            self.assertEqual(
+                TestCase.port,
+                TestCase.server_thread.port,
+                f"Did not use specified port for LiveServerTestCase thread: "
+                f"{TestCase.port}",
+            )
+        finally:
+            TestCase.doClassCleanups()
 
 
 class LiveServerThreadedTests(LiveServerBase):