minor symfony#26319 Use long array syntax (ro0NL)

This PR was merged into the 3.4 branch.

Discussion
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Use long array syntax

| Q             | A
| ------------- | ---
| Branch?       | 3.4
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no     <!-- see https://symfony.com/bc -->
| Deprecations? | no
| Tests pass?   | yes    <!-- please add some, will be required by reviewers -->
| Fixed tickets | #...   <!-- #-prefixed issue number(s), if any -->
| License       | MIT
| Doc PR        | symfony/symfony-docs#... <!-- required for new features -->

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Commits
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2abb8a4 Use long array syntax

Author: nicolas-grekas

src/Symfony/Component/DependencyInjection/Tests/Compiler/MergeExtensionConfigurationPassTest.php

@@ -110,7 +110,7 @@ public function testProcessedEnvsAreIncompatibleWithResolve()
     {
         $container = new ContainerBuilder();
         $container->registerExtension(new BarExtension());
-        $container->prependExtensionConfig('bar', []);
+        $container->prependExtensionConfig('bar', array());
 
         (new MergeExtensionConfigurationPass())->process($container);
     }