bug symfony#50937 [Form] fetch all known ChoiceType values at once (xabbuh)

This PR was merged into the 5.4 branch.

Discussion
----------

[Form] fetch all known ChoiceType values at once

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| Tickets       | Fix symfony#50898
| License       | MIT
| Doc PR        |

Commits
-------

5e0f832 fetch all known ChoiceType values at once

Author: fabpot

src/Symfony/Component/Form/Extension/Core/Type/ChoiceType.php

@@ -165,11 +165,9 @@ public function buildForm(FormBuilderInterface $builder, array $options)
                         }
                     }
                 } else {
-                    foreach ($data as $value) {
-                        if ($choiceList->getChoicesForValues([$value])) {
-                            $knownValues[] = $value;
-                            unset($unknownValues[$value]);
-                        }
+                    foreach ($choiceList->getChoicesForValues($data) as $key => $choice) {
+                        $knownValues[] = $data[$key];
+                        unset($unknownValues[$data[$key]]);
                     }
                 }