minor symfony#26077 [Workflow] Avoid risky tests (lyrixx)

This PR was merged into the 4.1-dev branch.

Discussion
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[Workflow] Avoid risky tests

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

Commits
-------

d590ef2 [Workflow] Avoid risky tests

Author: lyrixx

src/Symfony/Component/Workflow/Tests/RegistryTest.php

@@ -35,7 +35,13 @@ protected function tearDown()
      */
     public function testAddIsDeprecated()
     {
-        $this->registry->add(new Workflow(new Definition(array(), array()), $this->getMockBuilder(MarkingStoreInterface::class)->getMock(), $this->getMockBuilder(EventDispatcherInterface::class)->getMock(), 'workflow1'), $this->createSupportStrategy(Subject1::class));
+        $registry = new Registry();
+
+        $registry->add($w = new Workflow(new Definition(array(), array()), $this->getMockBuilder(MarkingStoreInterface::class)->getMock(), $this->getMockBuilder(EventDispatcherInterface::class)->getMock(), 'workflow1'), $this->createSupportStrategy(Subject1::class));
+
+        $workflow = $registry->get(new Subject1());
+        $this->assertInstanceOf(Workflow::class, $workflow);
+        $this->assertSame('workflow1', $workflow->getName());
     }
 
     public function testGetWithSuccess()