Broken JRuby and UTF-8 method names

Here's a test case for irb:

``` ruby
class A
  define_method 'проверка', lambda { p 'nunu' }
  p instance_method 'проверка'
end
```

Fails with `NameError: undefined method` on JRuby-1.7.6
Pass ok on MRI and RBX

Here's a fix:

```
class A
  define_method :'проверка', lambda { p 'nunu' }
  p instance_method :'проверка'
end
```

For me it seems broken. JRuby 1.7.4 passed this test.
