feature #9837 [Form] added getter to transformer chain (cordoval)

This PR was merged into the 2.5-dev branch.

Discussion
----------

[Form] added getter to transformer chain

| Q             | A
| ------------- | ---
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #9503
| License       | MIT
| Doc PR        | na

Commits
-------

3565d96 added getter to transformer chain

src/Symfony/Component/Form/Extension/Core/DataTransformer/DataTransformerChain.php

@@ -83,4 +83,12 @@ public function reverseTransform($value)
 
         return $value;
     }
+
+    /**
+     * @return DataTransformerInterface[]
+     */
+    public function getTransformers()
+    {
+        return $this->transformers;
+    }
 }