fix(h5): Compatible with safari

packages/webpack-uni-pages-loader/lib/util.js

@@ -42,6 +42,7 @@ function hasOwn (obj, key) {
 }
 
 function trimMPJson (json) {
+  delete json.maxWidth
   delete json.topWindow
   delete json.leftWindow
   delete json.rightWindow

src/platforms/h5/components/app/layout.vue

@@ -420,7 +420,7 @@ export default {
 
   .uni-mask+.uni-left-window,
   .uni-mask+.uni-right-window {
-    position: absolute;
+    position: fixed;
   }
 
   .uni-app--showlayout+uni-tabbar {