Summary:
When I was testing React Native 0.62-rc.1, I noticed that console was showing a warning for Require Cycle as shown in image below

This is because ScrollResponder was importing `ScrollView` to get the `typeof ScrollView`.
I've made an export for ScrollView type in `ScrollView` so that Require cycle warning will not show up.
## Changelog
[General] [Fixed] - Remove Require cycle warning.
Pull Request resolved: https://github.com/facebook/react-native/pull/27851
Differential Revision: D19577644
Pulled By: cpojer
fbshipit-source-id: 257b9421a91244d69394375102cfbe683326bba2