minor #20870 Minor fixes for 3.2 (ogizanagi)

This PR was merged into the 3.2 branch.

Discussion
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Minor fixes for 3.2

| Q             | A
| ------------- | ---
| Branch?       | 3.2
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | N/A
| License       | MIT
| Doc PR        | N/A

This only fix minor issues in the codebase introduced in 3.2.

Refs:

- YamlEncoder symfony/symfony@9366a7d

- File helper: symfony/symfony@d9a8499

- VarDumper ClassStub: symfony/symfony@788f7e8

- Cache tag based invalidation symfony/symfony@19764af

- CacheWarmer for Serializer: symfony/symfony@810f469

- SymfonyStyle simplified test: symfony/symfony@85e5060

- Workflow Definition builder: symfony/symfony@ffaeba3

---

There are other issues in older branches, but I guess it's not worth it for them, as it'll only add more conflicts. But for 3.2, it should be feasible.

Commits
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7bdfc84 Minor fixes for 3.2

Author: nicolas-grekas

Command/WorkflowDumpCommand.php

@@ -17,7 +17,6 @@
 use Symfony\Component\Workflow\Dumper\GraphvizDumper;
 use Symfony\Component\Workflow\Dumper\StateMachineGraphvizDumper;
 use Symfony\Component\Workflow\Marking;
-use Symfony\Component\Workflow\Workflow;
 
 /**
  * @author Grégoire Pineau <lyrixx@lyrixx.info>

Controller/Controller.php

@@ -137,7 +137,7 @@ protected function json($data, $status = 200, $headers = array(), $context = arr
     protected function file($file, $fileName = null, $disposition = ResponseHeaderBag::DISPOSITION_ATTACHMENT)
     {
         $response = new BinaryFileResponse($file);
-        $response->setContentDisposition($disposition, $fileName === null ? $response->getFile()->getFileName() : $fileName);
+        $response->setContentDisposition($disposition, $fileName === null ? $response->getFile()->getFilename() : $fileName);
 
         return $response;
     }

Tests/DependencyInjection/FrameworkExtensionTest.php

@@ -20,7 +20,6 @@
 use Symfony\Component\Cache\Adapter\ProxyAdapter;
 use Symfony\Component\Cache\Adapter\RedisAdapter;
 use Symfony\Component\DependencyInjection\ContainerBuilder;
-use Symfony\Component\DependencyInjection\Definition;
 use Symfony\Component\DependencyInjection\DefinitionDecorator;
 use Symfony\Component\DependencyInjection\Loader\ClosureLoader;
 use Symfony\Component\DependencyInjection\ParameterBag\ParameterBag;