UIScrollView在xib/storyboard中超出屏幕

1.设置根view的Simulated Metrics

2.设置view的size

设置完之后，就可以在storyboard中看到完整的设计页面了。

参考链接：

1.https://stackoverflow.com/questions/12905568/how-to-use-uiscrollview-in-storyboard?answertab=votes#tab-top

2.https://developer.apple.com/library/content/technotes/tn2154/_index.html

3.https://stackoverflow.com/questions/27877857/constraints-on-uiscrollview-with-paging