Show the number of reproducers saved

### Describe the desired feature
It would be nice to know if there's actually reproducers saved and that the folder isn't empty 
```
[2023-06-29 11:30:25.54] Saving test reproducers... Done! (0.000005s)
[2023-06-29 11:30:25.54] Saving corpus... ^[[ADone! (1.200988s)
```