interception_spec: add a failing test (SystemStackError stuff)

[kyrylo]

Original issue: https://github.com/pry/pry/issues/942

The problem occurs in pry-rescue plugin, which the original poster uses. I really wished to fix that myself, but I stumbled upon the wall. So I just added a failing test.

The failing test errors with the following message (on 1.9.3 and higher): can't modify frozen object (RuntimeError). Notice that this time it's frozen object, not Class.

On 1.8.7 the error message is different (BTW, I think we, Ruby developers, should forget about 1.8.7 now): NameError: undefined local variable or method shoulder'`. I'm not sure, but it looks like it cannot retrieve the correct binding.

I discovered that the problem lies somewhere around that line: https://github.com/ConradIrwin/interception/blob/e6259a786b1f9715127e9a26491331c5c525e549/ext/interception.c#L47

For what it's worth, I also found that SystemStackError inherits from Exception. It also freezes the message error string, but I don't think that's relevant. https://github.com/ruby/ruby/blob/bbe36f64a065dd6124b119590c5d4e5370c893e5/proc.c#L2154-L2157

[vincentwoo]

@ConradIrwin is there any chance you could pick this back up? The system stack errors seem to be related to something deep in Interception, and I can't fix it from in pry-rescue land.