Minor tweak to js printer (#10954)

scripts/tools/eslint-plugin-prettier-internal-rules/no-identifier-n.js

@@ -34,7 +34,7 @@ module.exports = {
 
         /* istanbul ignore next */
         if (!variable) {
-          throw new Error("Unexpected case.");
+          return;
         }
 
         if (!variables.has(variable)) {