bpo-37193: Remove thread objects which finished process its request (GH-23127)

This reverts commit aca67da4fe68d5420401ac1782203d302875eb27.
diff --git a/Lib/test/test_socketserver.py b/Lib/test/test_socketserver.py
index 7cdd115..954e033 100644
--- a/Lib/test/test_socketserver.py
+++ b/Lib/test/test_socketserver.py
@@ -277,6 +277,13 @@ class MyHandler(socketserver.StreamRequestHandler):
             t.join()
             s.server_close()
 
+    def test_close_immediately(self):
+        class MyServer(socketserver.ThreadingMixIn, socketserver.TCPServer):
+            pass
+
+        server = MyServer((HOST, 0), lambda: None)
+        server.server_close()
+
     def test_tcpserver_bind_leak(self):
         # Issue #22435: the server socket wouldn't be closed if bind()/listen()
         # failed.
@@ -491,6 +498,22 @@ def shutdown_request(self, request):
         self.assertEqual(server.shutdown_called, 1)
         server.server_close()
 
+    def test_threads_reaped(self):
+        """
+        In #37193, users reported a memory leak
+        due to the saving of every request thread. Ensure that
+        not all threads are kept forever.
+        """
+        class MyServer(socketserver.ThreadingMixIn, socketserver.TCPServer):
+            pass
+
+        server = MyServer((HOST, 0), socketserver.StreamRequestHandler)
+        for n in range(10):
+            with socket.create_connection(server.server_address):
+                server.handle_request()
+        self.assertLess(len(server._threads), 10)
+        server.server_close()
+
 
 if __name__ == "__main__":
     unittest.main()