merged branch venu/groups_argument_fix (PR #8422)

This PR was merged into the 2.2 branch.

Discussion
----------

[Validator] Fixed groups argument misplace for validateValue method from validator class

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

Signature of validateValue method in ExecutionContext Class is this.
```
public function validateValue($value, $constraints, $subPath = '', $groups = null)
```

But this was called wrongly in Validator Class.

Commits
-------

d3eb9b7 [Validator] Fixed groups argument misplace for validateValue method from validator class

src/Symfony/Component/Validator/Validator.php

@@ -186,7 +186,7 @@ class Validator implements ValidatorInterface
                 );
             }
 
-            $context->validateValue($value, $constraint, $groups);
+            $context->validateValue($value, $constraint, '', $groups);
         }
 
         return $context->getViolations();