servo: Merge #19437 - Remove 5 second pause in `./mach test-unit` (from servo:SimonSapin-patch-1); r=jdm

Details of why this pause happens in the first place are at https://github.com/servo/servo/issues/19439.

Source-Repo: https://github.com/servo/servo
Source-Revision: ba0240a3887e828a084929ab5c8952800ab01123

--HG--
extra : subtree_source : https%3A//hg.mozilla.org/projects/converted-servo-linear
extra : subtree_revision : 4c0b1e68939a749f50714e8f0f5c7dfdcbddfe15

servo/tests/unit/net/lib.rs

@@ -103,7 +103,7 @@ fn fetch_with_cors_cache(request: &mut Request, cache: &mut CorsCache) -> Respon
 
 fn make_server<H: Handler + 'static>(handler: H) -> (Listening, ServoUrl) {
     // this is a Listening server because of handle_threads()
-    let server = Server::http("0.0.0.0:0").unwrap().handle_threads(handler, 1).unwrap();
+    let server = Server::http("0.0.0.0:0").unwrap().handle_threads(handler, 2).unwrap();
     let url_string = format!("http://localhost:{}", server.socket.port());
     let url = ServoUrl::parse(&url_string).unwrap();
     (server, url)