Issue 4795 - Use modern JavaScript syntax

qunit/tests/prefs.js

 "use strict";
 
 {
   module("Preferences",
   {
-    setup: function()
+    setup()
     {
       preparePrefs.call(this);
     },
 
-    teardown: function()
+    teardown()
     {
       restorePrefs.call(this);
     }
   });
 
   function checkPrefExists(name, expectedValue, description, assert)
   {
     let done = assert.async();
     let key = "pref:" + name;
     chrome.storage.local.get(key, items =>
@@ skipping 72 matching lines @@
     deepEqual(Prefs.notificationdata, {foo:1, bar: 2}, "Prefs object returns the correct value after setting pref to non-default value");
     checkPrefExists("notificationdata", true, "User-defined pref has been created", assert);
     checkPref("notificationdata", {foo:1, bar: 2}, "Value has been written", assert);
 
     delete Prefs.notificationdata.foo;
     delete Prefs.notificationdata.bar;
     Prefs.notificationdata = JSON.parse(JSON.stringify(Prefs.notificationdata));
     deepEqual(Prefs.notificationdata, {}, "Prefs object returns the correct value after setting pref to default value");
   });
 }