minor #13328 [Yaml] maked a test as being for deprecated feature (fabpot)

This PR was merged into the 2.7 branch.

Discussion
----------

[Yaml] maked a test as being for deprecated feature

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

Commits
-------

651f5fb [Yaml] maked a test as being for deprecated feature

src/Symfony/Component/Yaml/Tests/YamlTest.php

@@ -23,7 +23,7 @@ class YamlTest extends \PHPUnit_Framework_TestCase
         $this->assertEquals($data, $parsed);
     }
 
-    public function testParseFromFile()
+    public function testLegacyParseFromFile()
     {
         $filename = __DIR__.'/Fixtures/index.yml';
         $contents = file_get_contents($filename);