Karma: Tests not picked up with top-level describe()

Karma does not detect or run tests when using top-level `describe()` (as opposed to `suite()`).

```typescript
import { describe } from 'razmin';
describe(it => { ... });
```

Works just fine with:
```typescript
import { suite } from 'razmin';
suite(describe => {
    describe(it => { ... });
});
```