Divide by negative zero does not keep sign.

Jerry version:

```
Checked revision: e84109f
Build command: ./tools/build.py --clean
```


OS:

```
Ubuntu 14.04.3 LTS
```


Test case:

```
1 / (0 * (-1))
```

Result:

```
$ node
> 1 / (0 * (-1))
-Infinity

$ jsc
>>> 1 / (0 * (-1))
-Infinity

$ jerry 
jerry> 1 / (0 * (-1))
Infinity
```