Summary:
Relates to #22100.
I left 2 `$FlowFixMe`s as I was not sure how to handle generic `React.Element<>` and which native props can I pass to ScrollView (would be cool to document it once we got proper types there).
I also got rid of `InternalScrollViewType` because we have better typings in original `ScrollView` now.
Pull Request resolved: https://github.com/facebook/react-native/pull/22301
Reviewed By: TheSavior
Differential Revision: D13103990
Pulled By: RSNara
fbshipit-source-id: 9664ee9d7f570b00992215e10901e5317f24fe5c