CFG treats diverging calls as its completely own path out of the function.
While this makes sense, it should also mean that a panic should increase the cyclomatic
complexity. Instead it decreases it.
Minimal example:
```rust
if a {
b
} else {
panic!("cake");
}
d
```
creates the following graph
```dot
digraph G {
"if a" -> "b"
"if a" -> "panic!(\"cake\")"
"b" -> c
}
```
which has a CC of 1 (3 - 4 + 2). A CC of 1 means there is one path through the program.
Obviously that is wrong. There are two paths. One returning normally, and one panicking.
