test: prefer enUS (#8144)

test/demo.ts

@@ -1,11 +1,8 @@
 import { h } from 'vue';
 import Locale from '../src/locale';
-import enUS from '../src/locale/lang/en-US';
 import { mount, later } from '.';
 import { DemoLocaleMixin } from '../docs/site/demo-locale';
 
-Locale.use('en-US', enUS);
-
 const EmptyComponent = {
   render() {
     return h('div', [this.$slots.default()]);

test/index.ts

@@ -1,4 +1,8 @@
 import './plugin';
+import Locale from '../src/locale';
+import enUS from '../src/locale/lang/en-US';
+
+Locale.use('en-US', enUS);
 
 // promisify setTimeout
 export function later(delay = 0): Promise<void> {