feat(mp): add $shouldDiffData

packages/vue-cli-plugin-uni/packages/mp-vue/dist/mp.runtime.esm.js

 /*!
  * Vue.js v2.6.11
- * (c) 2014-2019 Evan You
+ * (c) 2014-2020 Evan You
  * Released under the MIT License.
  */
 /*  */
@@ -5634,7 +5634,7 @@ var patch = function(oldVnode, vnode) {
     Object.keys(data).forEach(function (key) { //仅同步 data 中有的数据
       mpData[key] = mpInstance.data[key];
     });
-    var diffData = diff(data, mpData);
+    var diffData = this.$shouldDiffData === false ? data : diff(data, mpData);
     if (Object.keys(diffData).length) {
       if (process.env.VUE_APP_DEBUG) {
         console.log('[' + (+new Date) + '][' + (mpInstance.is || mpInstance.route) + '][' + this._uid +