Fix call to an undefined method Drupal\Tests\components\Kernel\TwigExtensionTest::getName()

Problem/Motivation

Phpstan is reporting multiple calls to an undefined method getName()

 ------ ------------------------------------------------------------------------------------------ 
  Line   tests/src/Kernel/TwigExtensionTest.php                                                    
 ------ ------------------------------------------------------------------------------------------ 
  43     Call to an undefined method Drupal\Tests\components\Kernel\TwigExtensionTest::getName().  
         🪪  method.notFound                                                                       
  75     Call to an undefined method Drupal\Tests\components\Kernel\TwigExtensionTest::getName().  
         🪪  method.notFound                                                                       
  125    Call to an undefined method Drupal\Tests\components\Kernel\TwigExtensionTest::getName().  
         🪪  method.notFound                                                                       
  174    Call to an undefined method Drupal\Tests\components\Kernel\TwigExtensionTest::getName().  
         🪪  method.notFound                                                                       
 ------ ------------------------------------------------------------------------------------------ 

 ------ ----------------------------------------------------------------------------------------------- 
  Line   tests/src/Unit/TwigExtensionFiltersTest.php                                                    
 ------ ----------------------------------------------------------------------------------------------- 
  279    Call to an undefined method Drupal\Tests\components\Unit\TwigExtensionFiltersTest::getName().  
         🪪  method.notFound                                                                            
 ------ ----------------------------------------------------------------------------------------------- 

Steps to reproduce

Proposed resolution

Remaining tasks

User interface changes

API changes

Data model changes