minor symfony#21171 Added missing headers in fixture files (iltar)

This PR was merged into the 3.1 branch.

Discussion
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Added missing headers in fixture files

| Q             | A
| ------------- | ---
| Branch?       | 3.1
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | n/a
| Fixed tickets | ~
| License       | MIT
| Doc PR        | ~

The headers were missing in a few files as mentioned in symfony#21164 (comment)

Commits
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c9c2474 Added missing headers in fixture files

Author: nicolas-grekas

src/Symfony/Component/HttpKernel/Tests/Fixtures/Controller/BasicTypesController.php

@@ -1,5 +1,14 @@
 <?php
 
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
 namespace Symfony\Component\HttpKernel\Tests\Fixtures\Controller;
 
 class BasicTypesController

src/Symfony/Component/HttpKernel/Tests/Fixtures/Controller/ExtendingRequest.php

@@ -1,5 +1,14 @@
 <?php
 
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
 namespace Symfony\Component\HttpKernel\Tests\Fixtures\Controller;
 
 use Symfony\Component\HttpFoundation\Request;

src/Symfony/Component/HttpKernel/Tests/Fixtures/Controller/VariadicController.php

@@ -1,5 +1,14 @@
 <?php
 
+/*
+ * This file is part of the Symfony package.
+ *
+ * (c) Fabien Potencier <fabien@symfony.com>
+ *
+ * For the full copyright and license information, please view the LICENSE
+ * file that was distributed with this source code.
+ */
+
 namespace Symfony\Component\HttpKernel\Tests\Fixtures\Controller;
 
 class VariadicController