Add a setup file that configures the React adapter. Fix one deprecated usage for ProjectLoaderHOC tests.

There are some tests still broken, but these weren't called out by Enzyme.

Adding `import 'chromedriver';` causes the module to register the path
to `chromedriver` / `chromedriver.exe` automatically, fixing this error:
```
The ChromeDriver could not be found on the current PATH. Please download the latest version of the ChromeDriver from http://chromedriver.storage.googleapis.com/index.html and ensure it can be found on your PATH.
        at Error (native)
```

This should fix the integration test failures on the extensions branch.
Thanks @paulkaplan for figuring this out!