Replace usage of arguments in arrow function

arguments is not available in arrow function so it is simpler to use rest
parameters.

issue11493
review419181003

src/common.js

@@ -3975,8 +3975,7 @@
     };
 
     Sao.common.debounce = function(func, wait) {
-        return () => {
-            var args = [].slice(arguments);
+        return (...args) => {
             clearTimeout(func._debounceTimeout);
             func._debounceTimeout = setTimeout(() => {
                 func.apply(this, args);

src/screen.js

@@ -1965,11 +1965,11 @@
                     (attributes.states || {})).pre_validate || [];
                 prms.push(record.validate(fields, false, domain));
             }
-            return jQuery.when.apply(jQuery, prms).then(() => {
+            return jQuery.when.apply(jQuery, prms).then((...args) => {
                 var record;
                 for (var i = 0; i < selected_records.length; i++) {
                     record = selected_records[i];
-                    var result = arguments[i];
+                    var result = args[i];
                     if (result) {
                         continue;
                     }