Confusing counter for system tests

Counter starts from zero:

```
INFO: Started running Flow over heated plate (fluid-openfoam, solid-openfoam),  0/2
```

and goes up to N-1:

```
 INFO: Started running Perpendicular flap (fluid-openfoam, solid-calculix),  1/2
```

This is confusing, let's make it start from 1.