Summary:
Use `getChildDrawingOrder` instead of reordering views. The old implementation didn't work properly when `removeClippedSubviews` was enabled and this one should have better performance since we don't play with the view hierarchy at all.
This fixes weird bugs with sticky headers in `SectionList` and allows removing the hack that disabled `removeClippedSubviews` when using sticky section headers.
**Test plan**
Tested using the SectionList and ListViewPaging examples that use sticky headers which uses z-index.
Closes https://github.com/facebook/react-native/pull/13105
Reviewed By: sahrens
Differential Revision: D4765869
Pulled By: achen1
fbshipit-source-id: be3c824658a3ce965b6e7324ad95c77cbd8a86ae
9a51fa8e15