Issue #3483321 by tr: Add declare(strict_types=1) to all test modules

Closes #3483321

tests/modules/typed_data_global_context_test/src/ContextProvider/SimpleTestContext.php

 <?php
 
+declare(strict_types=1);
+
 namespace Drupal\typed_data_global_context_test\ContextProvider;
 
 use Drupal\Core\Plugin\Context\Context;