Revert "Federation outbound proxy" (#15910)

Revert "Federation outbound proxy (#15773)"

This reverts commit b07b14b494.

tests/http/test_proxy.py

@@ -1,53 +0,0 @@
-# Copyright 2023 The Matrix.org Foundation C.I.C.
-#
-# Licensed under the Apache License, Version 2.0 (the "License");
-# you may not use this file except in compliance with the License.
-# You may obtain a copy of the License at
-#
-#     http://www.apache.org/licenses/LICENSE-2.0
-#
-# Unless required by applicable law or agreed to in writing, software
-# distributed under the License is distributed on an "AS IS" BASIS,
-# WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
-# See the License for the specific language governing permissions and
-# limitations under the License.
-from typing import Set
-
-from parameterized import parameterized
-
-from synapse.http.proxy import parse_connection_header_value
-
-from tests.unittest import TestCase
-
-
-class ProxyTests(TestCase):
-    @parameterized.expand(
-        [
-            [b"close, X-Foo, X-Bar", {"Close", "X-Foo", "X-Bar"}],
-            # No whitespace
-            [b"close,X-Foo,X-Bar", {"Close", "X-Foo", "X-Bar"}],
-            # More whitespace
-            [b"close,    X-Foo,      X-Bar", {"Close", "X-Foo", "X-Bar"}],
-            # "close" directive in not the first position
-            [b"X-Foo, X-Bar, close", {"X-Foo", "X-Bar", "Close"}],
-            # Normalizes header capitalization
-            [b"keep-alive, x-fOo, x-bAr", {"Keep-Alive", "X-Foo", "X-Bar"}],
-            # Handles header names with whitespace
-            [
-                b"keep-alive, x  foo, x bar",
-                {"Keep-Alive", "X  foo", "X bar"},
-            ],
-        ]
-    )
-    def test_parse_connection_header_value(
-        self,
-        connection_header_value: bytes,
-        expected_extra_headers_to_remove: Set[str],
-    ) -> None:
-        """
-        Tests that the connection header value is parsed correctly
-        """
-        self.assertEqual(
-            expected_extra_headers_to_remove,
-            parse_connection_header_value(connection_header_value),
-        )