increase the scenarii per proof when coverage enable to better cover conditions on generated types

Author: Baptouuuu

blackbox.php

@@ -22,7 +22,7 @@
                     ->dumpTo('coverage.clover')
                     ->enableWhen(true),
             )
-            ->scenariiPerProof(1),
+            ->scenariiPerProof(50),
     )
     ->tryToProve(Load::everythingIn(__DIR__.'/proofs/'))
     ->exit();