perf: inverse loop order (#4780)

Author: romgrk

compat/src/util.js

@@ -7,8 +7,8 @@ export const assign = Object.assign;
  * @returns {boolean}
  */
 export function shallowDiffers(a, b) {
-	for (let i in a) if (i !== '__source' && !(i in b)) return true;
-	for (let i in b) if (i !== '__source' && a[i] !== b[i]) return true;
+	for (let i in a) if (i !== '__source' && a[i] !== b[i]) return true;
+	for (let i in b) if (i !== '__source' && !(i in a)) return true;
 	return false;
 }