bug #22647 [VarDumper] Fix dumping of non-nested stubs (nicolas-grekas)

This PR was merged into the 2.7 branch.

Discussion
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[VarDumper] Fix dumping of non-nested stubs

| Q             | A
| ------------- | ---
| Branch?       | 2.7
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | -
| License       | MIT
| Doc PR        | -

Commits
-------

dd5b7a632b [VarDumper] Fix dumping of non-nested stubs

src/Symfony/Component/VarDumper/Caster/StubCaster.php

@@ -29,8 +29,10 @@ class StubCaster
             $stub->handle = $c->handle;
             $stub->cut = $c->cut;
 
-            return array();
+            $a = array();
         }
+
+        return $a;
     }
 
     public static function cutInternals($obj, array $a, Stub $stub, $isNested)