[bugfix] Toast: edundant instance when sync called multil times

packages/toast/index.js

@@ -1,6 +1,6 @@
 import Vue from 'vue';
 import VueToast from './Toast';
-import { isObj, isServer, isInDocument } from '../utils';
+import { isObj, isServer } from '../utils';
 
 const defaultOptions = {
   type: 'text',
@@ -38,7 +38,7 @@ function createInstance() {
     return {};
   }
 
-  if (!queue.length || multiple || !isInDocument(queue[0].$el)) {
+  if (!queue.length || multiple) {
     const toast = new (Vue.extend(VueToast))({
       el: document.createElement('div')
     });

packages/toast/test/index.spec.js

@@ -1,4 +1,6 @@
+import Vue from 'vue';
 import Toast from '..';
+import ToastVue from '../Toast';
 import { transitionStub, later } from '../../../test/utils';
 
 transitionStub();
@@ -86,3 +88,8 @@ test('onClose callback', () => {
   Toast.allowMultiple(false);
   expect(onClose).toHaveBeenCalledTimes(1);
 });
+
+test('register component', () => {
+  Vue.use(Toast);
+  expect(Vue.component(ToastVue.name)).toBeTruthy();
+});