Close the client connection after faulty response framing

A response framed by Transfer-Encoding next to a Content-Length, or an
HTTP/1.0 response with Transfer-Encoding, left the connection open for
the next request, though RFC 9112 6.1 has such framing treated as faulty
and the connection closed after it. Close it, with the check the server
makes for requests now shared.

test/test.cc

@@ -22664,6 +22664,29 @@ TEST(ClientResponseSmugglingTest, BodylessResponseNotRejected) {
   }
 }
 
+// RFC 9112 6.1: Transfer-Encoding next to a Content-Length, or in an HTTP/1.0
+// response, is faulty framing, so the connection is not reused after it.
+TEST(ClientResponseSmugglingTest, FaultyTransferEncodingClosesConnection) {
+  for (const char *response : {"HTTP/1.1 200 OK\r\n"
+                               "Content-Length: 0\r\n"
+                               "Transfer-Encoding: chunked\r\n"
+                               "\r\n"
+                               "5\r\nhello\r\n0\r\n\r\n",
+                               "HTTP/1.0 200 Connection established\r\n"
+                               "Connection: keep-alive\r\n"
+                               "Transfer-Encoding: chunked\r\n"
+                               "\r\n"
+                               "5\r\nhello\r\n0\r\n\r\n"}) {
+    with_single_response(response, [&](Client &cli) {
+      cli.set_keep_alive(true);
+      auto res = cli.Get("/");
+      ASSERT_TRUE(res) << response;
+      EXPECT_EQ("hello", res->body);
+      EXPECT_FALSE(cli.is_socket_open()) << response;
+    });
+  }
+}
+
 // A payload max length of 0 means no limit, however the body is framed.
 TEST(PayloadMaxLengthZeroTest, ClientReadsChunkedAndUnframedResponse) {
   for (const char *response : {"HTTP/1.1 200 OK\r\n"