Segmentation fault in mb_strimwidth()

### Description

The following code:

```php
<?php
echo mb_strimwidth('The quick brown fox', 0, 8);
```

Process crashed with SIGSEGV.

But I expected this output instead:
```
The quic
```


### PHP Version

git.master | released 2022-08-04 (3v4l.org)

### Operating System

_No response_