requestLayout() improperly called by xxxxxxxxxxxxxxxxxxx ScrollViewContainer 问题

当scrollview内的内容更改大小时，Scrollview不会自行调整大小。效果是，当内容变小时，内容将留在原来的位置，当内容变大时，无法看到。仅当ScrollView位于作为MasterDetailPage的详细信息的页面内时才会发生这种情况。如果Detail是NavigationPage，则Scrollview可以正常工作。

requestLayout() improperly called by md5b60ffeb829f638581ab2bb9b1a7f4f3f.ScrollViewContainer{67a6572 V.E...... ......ID 0,0-720,1136} during layout: running second layout pass

requestLayout() improperly called by md5270abb39e60627f0f200893b490a1ade.NavigationPageRenderer{1d5c6ce V.E...... ......I. 0,0-720,1136 #1} during second layout pass: posting in next frame

参考：

https://github.com/xamarin/Xamarin.Forms/issues/1332