Add ArgumentError to instance_eval

## current
```bash
$ mirb
mirb - Embeddable Interactive Ruby Shell

This is a very early version, please test and report errors.
Thanks :)

> instance_eval
Segmentation fault: 11
```

## fixed
```bash
$ mirb
mirb - Embeddable Interactive Ruby Shell

This is a very early version, please test and report errors.
Thanks :)

> instance_eval
ArgumentError: no block given
>
```