[php-src] Issue #20695: Assertion failure in normalize_value() when parsing malformed INI input via parse_ini_string()

Issue: https://github.com/php/php-src/issues/20695
Author: vi3tL0u1s

### Description

The following code:

```php
<?php
class a {
    function __destruct() {
        try {
            array_merge([' ' => [PHP_INT_MAX => null]], ['foo' == str_repeat('a', 2)],);
        } catch (Throwable $e) {}
        var_dump(parse_ini_string(<<<INI
            8 [[$obj] = !!$]
            INI, TRUE, INI_SCANNER_TYPED));
        }
}
new a;
```

Resulted in this output:
```
php: /path/to/php-src/Zend/zend_ini_parser.y:317: normalize_value: Assertion `(*(zv)).u2.extra == 0 || (*(zv)).u2.extra == 1' failed.
Aborted
```

Commit:

```
2ee5e6b432c7ed51ff7296522c123551975be95b
```

Configurations:

```bash
CC="clang" CXX="clang++" CFLAGS="-fsanitize=address -g -O0" CXXFLAGS="-fsanitize=address -g -O0" ./configure --enable-debug --enable-address-sanitizer --disable-shared --with-pic
```


### PHP Version

```plain
PHP 8.6.0-dev (cli) (built: Dec 13 2025 16:51:10) (NTS DEBUG)
Copyright (c) The PHP Group
Zend Engine v4.6.0-dev, Copyright (c) Zend Technologies
    with Zend OPcache v8.6.0-dev, Copyright (c), by Zend Technologies
```

### Operating System

Ubuntu 22.04