minor symfony#17194 [Bridge/Doctrine] Fix test case (nicolas-grekas)

This PR was merged into the 2.8 branch.

Discussion
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[Bridge/Doctrine] Fix test case

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

The choice_list vs choice_loader change is already applied on 3.0,
the `@group legacy` tags a test case that has been already removed in 3.0.
@webmozart or anyone else could you please have a quick look here and confirm it's ok?

Commits
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4ef2c33 [Bridge/Doctrine] Fix test case

Author: nicolas-grekas

src/Symfony/Bridge/Doctrine/Tests/Form/Type/EntityTypeTest.php

@@ -1194,15 +1194,18 @@ public function testLoaderCachingWithParameters()
             'property3' => 2,
         ));
 
-        $choiceList1 = $form->get('property1')->getConfig()->getOption('choice_list');
-        $choiceList2 = $form->get('property2')->getConfig()->getOption('choice_list');
-        $choiceList3 = $form->get('property3')->getConfig()->getOption('choice_list');
+        $choiceLoader1 = $form->get('property1')->getConfig()->getOption('choice_loader');
+        $choiceLoader2 = $form->get('property2')->getConfig()->getOption('choice_loader');
+        $choiceLoader3 = $form->get('property3')->getConfig()->getOption('choice_loader');
 
-        $this->assertInstanceOf('Symfony\Component\Form\ChoiceList\ChoiceListInterface', $choiceList1);
-        $this->assertSame($choiceList1, $choiceList2);
-        $this->assertSame($choiceList1, $choiceList3);
+        $this->assertInstanceOf('Symfony\Component\Form\ChoiceList\Loader\ChoiceLoaderInterface', $choiceLoader1);
+        $this->assertSame($choiceLoader1, $choiceLoader2);
+        $this->assertSame($choiceLoader1, $choiceLoader3);
     }
 
+    /**
+     * @group legacy
+     */
     public function testCacheChoiceLists()
     {
         $entity1 = new SingleIntIdEntity(1, 'Foo');