minor #13470 [2.7] Removed dead code and various cleaning (saro0h)

This PR was merged into the 2.7 branch.

Discussion
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[2.7] Removed dead code and various cleaning

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

In complement of these: symfony/symfony#13488 & symfony/symfony#13481

Commits
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9272f86 Removed dead code and various cleaning

Author: fabpot

Extension/Core/DataTransformer/NumberToLocalizedStringTransformer.php

@@ -13,7 +13,6 @@
 
 use Symfony\Component\Form\DataTransformerInterface;
 use Symfony\Component\Form\Exception\TransformationFailedException;
-use Symfony\Component\Form\Deprecated\NumberToLocalizedStringTransformer as Deprecated;
 
 /**
  * Transforms between a number type and a localized number with grouping

Extension/Validator/Constraints/Form.php

@@ -11,7 +11,6 @@
 
 namespace Symfony\Component\Form\Extension\Validator\Constraints;
 
-use Symfony\Component\Form\Extension\Validator\Constraints\Deprecated\Form as Deprecated;
 use Symfony\Component\Validator\Constraint;
 
 /**