minor #57966 [Form] skip tests requiring the intl extension if it's not installed (xabbuh)

This PR was merged into the 5.4 branch.

Discussion
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[Form] skip tests requiring the intl extension if it's not installed

| Q             | A
| ------------- | ---
| Branch?       | 5.4
| Bug fix?      | no
| New feature?  | no
| Deprecations? | no
| Issues        |
| License       | MIT

Commits
-------

141cb8765f skip tests requiring the intl extension if it's not installed

Author: nicolas-grekas

Tests/Extension/Core/DataTransformer/NumberToLocalizedStringTransformerTest.php

@@ -638,6 +638,8 @@ public function testReverseTransformSmallInt()
      */
     public function testReverseTransformENotation($output, $input)
     {
+        IntlTestHelper::requireFullIntl($this);
+
         \Locale::setDefault('en');
 
         $transformer = new NumberToLocalizedStringTransformer();