… false in ViolationMapper (issei-m)

This PR was squashed before being merged into the 2.3 branch (closes #18761).

Discussion
----------

[2.3] [Form] Modified iterator_to_array's 2nd parameter to false in ViolationMapper

| Q             | A
| ------------- | ---
| Branch?       | 2.3
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

For #18747

Commits
-------

7101cab [2.3] [Form] Modified iterator_to_array's 2nd parameter to false in ViolationMapper

… false in ViolationMapper (issei-m)

This PR was submitted for the 2.8 branch but it was merged into the 2.7 branch instead (closes #18747).

Discussion
----------

[2.8] [Form] Modified iterator_to_array's 2nd parameter to false in ViolationMapper

| Q             | A
| ------------- | ---
| Branch?       | 2.8
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | n/a
| License       | MIT
| Doc PR        | n/a

This bug was introduced in PR #17099. So does not represent in 2.8.2 or older.

If we have the following structure form:

```php
$builder = $formFactory->createBuilder();

$form = $builder
    ->add(
        $builder->create('person1_name', FormType::class, ['inherit_data' => true])
            ->add('first', TextType::class, ['property_path' => '[person1_first_name]'])
            ->add('last', TextType::class, ['property_path' => '[person1_last_name]'])
    )
    ->add(
        $builder->create('person2_name', FormType::class, ['inherit_data' => true])
            ->add('first', TextType::class, ['property_path' => '[person2_first_name]'])
            ->add('last', TextType::class, ['property_path' => '[person2_last_name]'])
    )
    ->getForm()
;
```

The following mapping for this form doesn't work correctly:

```php
$mapper = new ViolationMapper();
$mapper->mapViolation(new ConstraintViolation('', '', [], null, 'data[person1_first_name]', null), $form);

$form['person1_name']['first']->getErrors(); // empty
$form->getErrors(); // The violation is mapped to here instead.
```

## Cause

Because ViolationMapper uses `iterator_to_array` in [here](https://github.com/symfony/symfony/blob/f29d46f29b91ea5c30699cf6bdb8e65545d1dd26/src/Symfony/Component/Form/Extension/Validator/ViolationMapper/ViolationMapper.php#L165) to collect the sub forms.

`person1_name` and `person2_name` enable `inherit_data` option. So ViolationMapper will attempt to collect the sub forms of root form like this:

```php
[
    'first' => Form object, // root.person1_name.first
    'last'  => Form object, // root.person1_name.last
    'first' => Form object, // root.person2_name.first
    'last'  => Form object, // root.person2_name.last
]
```

As you can see, The name `first` and `last` are used in two places, thus we cannot get result like that.
(first/last of person1_name are overwritten by person2_name's)

So the violation will finally lost the form where it should map to. It should pass `false` to `iterator_to_array`'s 2nd parameter.

Commits
-------

ae38660 [2.8] [Form] Modified iterator_to_array's 2nd parameter to false in ViolationMapper