Constant argument removal removes some if conditions that throw exceptions #98

These are not inserted by the obfuscator, so it'd be nice if we could avoid removing them (but difficult!) - ultimately it's never going to be possible for the dummy argument removal to perfectly match the original unobfuscated code.

Similarly, it can be a bit too eager to remove arguments from some methods that only happen to be invoked with a single value by chance. However, I'm not sure if there's much we can do about that...