Add automated test scoring to the metric calculated by pub.dev.

[kf6gpe]

Suggested in this issue in the flutter repo: flutter/flutter#36934.

[isoos]

@kf6gpe thanks for submitting this. We want to implement this, but we'll need to have a good isolated environment for running the tests first.

[nerder]

Just a suggestion here (probably obvious, and most likely you already thought about it), maybe a first initial baby step for it will be to simply checking if tests are presents. This could be something very simple such as checking if a test directory exists and if there is something there.

[sigurdm]

Still no concrete plans, but bright dreams about this.