Suppress clippy warnings in tests/

This is a known issue as these kind of warnings are already disabled on
the lib.rs level in the crate.

Author: daniel-abramov

tests/client_headers.rs

@@ -1,4 +1,5 @@
 #![cfg(feature = "handshake")]
+#![allow(clippy::result_large_err)]
 
 use http::Uri;
 use std::{

tests/handshake.rs

@@ -1,4 +1,5 @@
 #![cfg(feature = "handshake")]
+#![allow(clippy::result_large_err)]
 use std::{
     net::TcpListener,
     thread::{sleep, spawn},

tests/url_feature.rs

@@ -1,5 +1,6 @@
 #![cfg(feature = "handshake")]
 #![cfg(feature = "url")]
+#![allow(clippy::result_large_err)]
 
 use std::{
     assert,