Remove redundant url clones

They are now redundant since now document.url() returns a struct rather
than a reference.

components/script/dom/htmlanchorelement.rs

@@ -615,5 +615,5 @@ fn follow_hyperlink(subject: &Element, hyperlink_suffix: Option<String>, referre
     debug!("following hyperlink to {}", url);
 
     let window = document.window();
-    window.load_url(url, false, referrer_policy);
+    window.load_url(url, false, false, referrer_policy);
 }