Lexing memory corruption

### Description

Most likely caused (or revealed) by https://github.com/php/php-src/commit/f291d37a1a7d78e841f40a4410359548bc73de1b.

The following code:

oss-fuzz Issue 55793

```php
<?yyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyyy&#
```

```
heap-buffer-overflow
```

But I expected this output instead:
```
```


### PHP Version

master

### Operating System

_No response_