minor symfony#23652 [Form] Static call TimezoneType::getTimezones (ro0NL)

This PR was merged into the 3.2 branch.

Discussion
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[Form] Static call TimezoneType::getTimezones

| Q             | A
| ------------- | ---
| Branch?       | 3.2
| Bug fix?      | no
| New feature?  | no <!-- don't forget updating src/**/CHANGELOG.md files -->
| BC breaks?    | no
| Deprecations? | no <!-- don't forget updating UPGRADE-*.md files -->
| Tests pass?   | yes
| Fixed tickets | #... <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!--highly recommended for new features-->

Spotted in symfony#23648

Commits
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fe48ab1 [Form] Static call TimezoneType::getTimezones

Author: ogizanagi

src/Symfony/Component/Form/Extension/Core/Type/TimezoneType.php

@@ -66,7 +66,7 @@ public function loadChoiceList($value = null)
             return $this->choiceList;
         }
 
-        return $this->choiceList = new ArrayChoiceList($this->getTimezones(), $value);
+        return $this->choiceList = new ArrayChoiceList(self::getTimezones(), $value);
     }
 
     /**