Fragment now works on both React and React Native, so use it.

Adds the logic to render TestHint only when the test mode is enabled
in order to be able to put independent TestHints in other places than
the TestConnectionInfo component.

Adds TestConnectionInfo component which exposes some internal app state
to the jitsi-meet-torture through the UI accessibility layer. This
component will render only if config.testing.testMode is set to true.