Bump react from 16.7.0 to 16.8.6 (#10935)

* Bump react from 16.7.0 to 16.8.6

Bumps [react](https://github.com/facebook/react/tree/HEAD/packages/react) from 16.7.0 to 16.8.6.
- [Release notes](https://github.com/facebook/react/releases)
- [Changelog](https://github.com/facebook/react/blob/master/CHANGELOG.md)
- [Commits](https://github.com/facebook/react/commits/v16.8.6/packages/react)

* Bump react-dom from 16.7.0 to 16.8.6

* Bump react-test-renderer from 16.7.0 to 16.8.6