minor #38191 [PhpUnitBridge] Fix error with ReflectionClass (sanmai)

This PR was merged into the 4.4 branch.

Discussion
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[PhpUnitBridge] Fix error with ReflectionClass

| Q             | A
| ------------- | ---
| Branch?       | 4.4
| Bug fix?      | yes
| New feature?  | no
| Deprecations? | no
| License       | MIT

Introduced in #38094. Wish I know how I missed that.

Commits
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ed1bffeed7 [PhpUnitBridge] Fix error with ReflectionClass

src/Symfony/Bridge/PhpUnit/Legacy/CoverageListenerTrait.php

@@ -109,7 +109,7 @@ class CoverageListenerTrait
 
         // Exclude internal classes; PHPUnit 9.1+ is picky about tests covering, say, a \RuntimeException
         $covers = array_filter($covers, function ($class) {
-            $reflector = new ReflectionClass($class);
+            $reflector = new \ReflectionClass($class);
 
             return $reflector->isUserDefined();
         });