same as `rand(endless_range)`

Before:
```
$ ruby -e 'rand(..1)'
Traceback (most recent call last):
	2: from -e:1:in `<main>'
	1: from -e:1:in `rand'
-e:1:in `-': nil can't be coerced into Integer (TypeError)
```

After:
```
$ ruby -e 'rand(..1)'
Traceback (most recent call last):
	1: from -e:1:in `<main>'
-e:1:in `rand': Numerical argument out of domain (Errno::EDOM)
```