Merge bitcoin#18596: test: Try once more when RPC connection fails on Windows

fab9899 test: Try once more when RPC connection fails on Windows (MarcoFalke)
faa6557 test: Document why connection is re-constructed on windows (MarcoFalke)
fa9f4f6 test: Remove python 3.4 workaround (MarcoFalke)
fae760f cirrus: Bump freebsd to 12.1 (MarcoFalke)

Pull request description:

  Fixes: bitcoin#18548

ACKs for top commit:
  hebasto:
    ACK fab9899, I have reviewed the code and it looks OK, I agree it can be merged.

Tree-SHA512: c4e9ed8d995b63a820ca66984f152ac216c83ba1f318b61b15c6d375c0e936c08f6bc3d38c255dddf3ee8952f848c7ababf684854e07a7c1b1d8504e6b7208ba

Author: MarcoFalke

.cirrus.yml

@@ -1,7 +1,7 @@
 task:
-  name: "FreeBsd 12.0 amd64  [GOAL: install]  [no depends, only system libs]"
+  name: "FreeBsd 12.1 amd64  [GOAL: install]  [no depends, only system libs]"
   freebsd_instance:
-    image: freebsd-12-0-release-amd64
+    image_family: freebsd-12-1  # https://cirrus-ci.org/guide/FreeBSD/
     cpu: 8
     memory: 8G
   timeout_in: 60m

test/functional/test_framework/authproxy.py

@@ -101,23 +101,26 @@ def _request(self, method, path, postdata):
         if os.name == 'nt':
             # Windows somehow does not like to re-use connections
             # TODO: Find out why the connection would disconnect occasionally and make it reusable on Windows
+            # Avoid "ConnectionAbortedError: [WinError 10053] An established connection was aborted by the software in your host machine"
             self._set_conn()
         try:
             self.__conn.request(method, path, postdata, headers)
             return self._get_response()
-        except http.client.BadStatusLine as e:
-            if e.line == "''":  # if connection was closed, try again
+        except (BrokenPipeError, ConnectionResetError):
+            # Python 3.5+ raises BrokenPipeError when the connection was reset
+            # ConnectionResetError happens on FreeBSD
+            self.__conn.close()
+            self.__conn.request(method, path, postdata, headers)
+            return self._get_response()
+        except OSError as e:
+            retry = (
+                '[WinError 10053] An established connection was aborted by the software in your host machine' in str(e))
+            if retry:
                 self.__conn.close()
                 self.__conn.request(method, path, postdata, headers)
                 return self._get_response()
             else:
                 raise
-        except (BrokenPipeError, ConnectionResetError):
-            # Python 3.5+ raises BrokenPipeError instead of BadStatusLine when the connection was reset
-            # ConnectionResetError happens on FreeBSD with Python 3.4
-            self.__conn.close()
-            self.__conn.request(method, path, postdata, headers)
-            return self._get_response()
 
     def get_request(self, *args, **argsn):
         AuthServiceProxy.__id_count += 1