bug #29501 [Form] filter out invalid language values (xabbuh)

This PR was merged into the 4.1 branch.

Discussion
----------

[Form] filter out invalid language values

| Q             | A
| ------------- | ---
| Branch?       | 4.1
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #23679
| License       | MIT
| Doc PR        |

Commits
-------

ed97568b8a filter out invalid language values

src/Symfony/Component/Form/ChoiceList/Loader/IntlCallbackChoiceLoader.php

@@ -30,11 +30,6 @@ class IntlCallbackChoiceLoader extends CallbackChoiceLoader
             return array();
         }
 
-        // If no callable is set, values are the same as choices
-        if (null === $value) {
-            return $values;
-        }
-
         return $this->loadChoiceList($value)->getChoicesForValues($values);
     }
 

src/Symfony/Component/Form/Tests/ChoiceList/Loader/IntlCallbackChoiceLoaderTest.php

@@ -84,6 +84,11 @@ class IntlCallbackChoiceLoaderTest extends TestCase
         );
     }
 
+    public function testLoadChoicesForValuesDropsNonExistentChoices()
+    {
+        $this->assertSame(array(), self::$loader->loadChoicesForValues(array('foo')));
+    }
+
     public function testLoadValuesForChoicesLoadsChoiceListOnFirstCall()
     {
         $this->assertSame(