Added test for classes that override raise (provides integration with Mulligan)

Hi Conrad,

I tried to update interception to handle the case where `Kernel#raise` might be called from another class' `#raise` method (for future compatibility with Mullligan). I wasn't able to figure it out because I don't think I fully understand the creation of bindings or if they are collected in a stack or not.

But, I figured I'd at least check in a test that would need to pass to verify that it works. It fails of course, but do you think this is enough for you to whip up a quick fix?

Best,

_ michael