Fails to detect possibly-impossible constant offset

```php
class A {
    const KEYS = ["one", "two"];
    const ARR = [
        "two" => 1,
        "three" => 2
    ];
}

foreach (A::KEYS as $key) {
    echo A::ARR[$key];
}
```
Expected: Possibly undefined array offset A::ARR["one"]
Actual: [No issues](https://phpstan.org/r/b4e3407d0fb84056403f04ff7d40252e)