Backout Host-header related change from #32024. (#32093)

#32024 broke a different set of nginx sites, and a more sophisticated fix for the case of a missing HTTP 1.1 `Host` header is required.

components/net/tests/fetch.rs

@@ -1359,15 +1359,6 @@ fn test_fetch_with_devtools() {
 
     headers.typed_insert::<UserAgent>(DEFAULT_USER_AGENT.parse().unwrap());
 
-    let host = if url.port().is_none() {
-        url.host_str().unwrap().to_string()
-    } else {
-        format!("{}:{}", url.host_str().unwrap(), url.port().unwrap())
-    };
-    headers.typed_insert(headers::Host::from(
-        host.parse::<http::uri::Authority>().unwrap(),
-    ));
-
     headers.insert(
         header::ACCEPT_ENCODING,
         HeaderValue::from_static("gzip, deflate, br"),

components/net/tests/http_loader.rs

@@ -266,8 +266,6 @@ fn test_request_and_response_data_with_network_messages() {
     //Creating default headers for request
     let mut headers = HeaderMap::new();
 
-    headers.insert(header::HOST, HeaderValue::from_static("bar.foo"));
-
     headers.insert(
         header::ACCEPT,
         HeaderValue::from_static("text/html,application/xhtml+xml,application/xml;q=0.9,*/*;q=0.8"),