Invalid messages logged to console

Upon upgrading to Ember 3.7.x, I found that the JavaScript console had strange messages being logged from this library, like:
```
Transition #Attempting URL transition to /myroute/123: undefined
Preparing to transition from '' to 'myroute'
0
Transitioned into 'myroute'
0
```

The 1st, 3rd, and 5th, messages all seem to stem from an incorrect check in the ``log`` function at:
https://github.com/tildeio/router.js/blob/master/lib/router/utils.ts#L74

I think ``if (arguments.length === 2)`` should be replaced with ``if (args.length === 2)``.