[change] Remove MaskedViewIOS

Ref #1352
Ref https://github.com/facebook/react-native/issues/23313

packages/babel-plugin-react-native-web/src/moduleMap.js

@@ -27,7 +27,6 @@ module.exports = {
   KeyboardAvoidingView: true,
   LayoutAnimation: true,
   Linking: true,
-  MaskedViewIOS: true,
   Modal: true,
   NativeEventEmitter: true,
   NativeModules: true,

packages/react-native-web/src/exports/MaskedViewIOS/index.js

@@ -1,2 +0,0 @@
-import UnimplementedView from '../../modules/UnimplementedView';
-export default UnimplementedView;

packages/react-native-web/src/index.js

@@ -72,7 +72,6 @@ import PointPropType from './exports/PointPropType';
 // compat (components)
 import DrawerLayoutAndroid from './exports/DrawerLayoutAndroid';
 import InputAccessoryView from './exports/InputAccessoryView';
-import MaskedViewIOS from './exports/MaskedViewIOS';
 import NavigatorIOS from './exports/NavigatorIOS';
 import PickerIOS from './exports/PickerIOS';
 import ProgressBarAndroid from './exports/ProgressBarAndroid';
@@ -170,7 +169,6 @@ export {
   // compat (components)
   DrawerLayoutAndroid,
   InputAccessoryView,
-  MaskedViewIOS,
   NavigatorIOS,
   PickerIOS,
   ProgressBarAndroid,