Default reporter should show a busy indicator

[sindresorhus]

Some people have been confused and thought AVA froze, just because it was stuck on showing one test title for a while. This can happen when a lot of async tests are run concurrently and it takes some time for them all to finish.

I'm thinking something simple like:

Or

From: https://github.com/sindresorhus/cli-spinners/blob/master/spinners.json

[jamestalmage]

👍

[kasperlewau]

👍