minor #58430 Remove a few unnecessary full qualifier (alexandre-daubois)

This PR was merged into the 7.2 branch.

Discussion
----------

Remove a few unnecessary full qualifier

| Q             | A
| ------------- | ---
| Branch?       | 7.2
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        | -
| License       | MIT

Remove full qualifier in places there are not present usually in the code base: mocks, already imported classes, expected exceptions.

Commits
-------

154306840f6 Remove a few unnecessary full qualifier

Tests/Fixtures/ParentDummy.php

@@ -66,7 +66,7 @@ class ParentDummy
     public $rootDummyItems;
 
     /**
-     * @var \Symfony\Component\PropertyInfo\Tests\Fixtures\RootDummy\RootDummyItem
+     * @var RootDummyItem
      */
     public $rootDummyItem;