bug #27281 [HttpKernel] Fix dealing with self/parent in ArgumentMetadataFactory (fabpot)

This PR was merged into the 3.4 branch.

Discussion
----------

[HttpKernel] Fix dealing with self/parent in ArgumentMetadataFactory

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Applies CS fixes that where merged on 4.0 to 3.4, embeds a fix in ArgumentMetadataFactory, which couldn't deal with self/parent type hints.

Commits
-------

ba5cb1a245 fixed CS

Exception/FlattenException.php

@@ -157,7 +157,7 @@ class FlattenException
         return $this->previous;
     }
 
-    public function setPrevious(FlattenException $previous)
+    public function setPrevious(self $previous)
     {
         $this->previous = $previous;
     }