Use == instead of match for tests against a single enum value

The performance of using == should now equal that of match, so many
identity methods can be simplified to a single line.

Fixes #1596.

src/components/script/dom/xmlhttprequestupload.rs

@@ -40,12 +40,9 @@ impl Reflectable for XMLHttpRequestUpload {
 
 impl XMLHttpRequestUploadDerived for EventTarget {
     fn is_xmlhttprequestupload(&self) -> bool {
-        match self.type_id {
-            XMLHttpRequestTargetTypeId(XMLHttpRequestUploadTypeId) => true,
-            _ => false
-        }
+        self.type_id == XMLHttpRequestTargetTypeId(XMLHttpRequestUploadTypeId)
     }
 }
 
 pub trait XMLHttpRequestUploadMethods {
-}
+}