minor #27508 [Finder] Update RealIteratorTestCase (flip111)

This PR was submitted for the master branch but it was squashed and merged into the 2.8 branch instead (closes #27508).

Discussion
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[Finder] Update RealIteratorTestCase

| Q             | A
| ------------- | ---
| Branch?       | 2.8
| Bug fix?      | no
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets | #27480
| License       | MIT
| Doc PR        | n/a

Makes the entire test directory empty instead of trying to delete particular files and directories. The old method failed when trying to remove a directory which was not empty.

Commits
-------

562262c [Finder] Update RealIteratorTestCase

Author: nicolas-grekas

Tests/Iterator/RealIteratorTestCase.php

@@ -60,11 +60,20 @@ public static function setUpBeforeClass()
 
     public static function tearDownAfterClass()
     {
-        foreach (array_reverse(self::$files) as $file) {
-            if (DIRECTORY_SEPARATOR === $file[strlen($file) - 1]) {
-                @rmdir($file);
+        $paths = new \RecursiveIteratorIterator(
+             new \RecursiveDirectoryIterator(self::$tmpDir, \RecursiveDirectoryIterator::SKIP_DOTS),
+             \RecursiveIteratorIterator::CHILD_FIRST
+         );
+
+        foreach ($paths as $path) {
+            if ($path->isDir()) {
+                if ($path->isLink()) {
+                    @unlink($path);
+                } else {
+                    @rmdir($path);
+                }
             } else {
-                @unlink($file);
+                @unlink($path);
             }
         }
     }