Build: Enforce ECMAScript 5 in tests via ESLint

Fixes gh-5542
Closes gh-5563

diff --git a/eslint.config.js b/eslint.config.js
index ceb943dbbea9e61d5ee3c4436faceed19a23bf1a..575c93fa4b0dec5f6f1a80cbee5dbb58c2c9dcb9 100644 (file)
--- a/eslint.config.js
+++ b/eslint.config.js
@@ -159,11 +159,13 @@ export default [
                        "test/data/core/jquery-iterability-transpiled.js"
                ],
                languageOptions: {
-                       ecmaVersion: 2015,
+                       ecmaVersion: 5,
                        sourceType: "script",
                        globals: {
                                ...globals.browser,
                                require: false,
+                               Promise: false,
+                               Symbol: false,
                                trustedTypes: false,
                                QUnit: false,
                                ajaxTest: false,