bug #19126 [PhpUnitBridge] use call_user_func() for PHP 5.3 compatibility (xabbuh)

This PR was merged into the 3.2-dev branch.

Discussion
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[PhpUnitBridge] use call_user_func() for PHP 5.3 compatibility

| Q             | A
| ------------- | ---
| Branch?       | master
| Bug fix?      | yes
| New feature?  | no
| BC breaks?    | no
| Deprecations? | no
| Tests pass?   | yes
| Fixed tickets |
| License       | MIT
| Doc PR        |

Not all callables can be called directly on PHP 5.3 (for example, `array('className', 'methodName')` does not work).

Commits
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8549e05 use call_user_func() for PHP 5.3 compatibility

src/Symfony/Bridge/PhpUnit/ErrorAssert.php

@@ -53,7 +53,7 @@ final class ErrorAssert
                 $triggeredMessages[] = $message;
             });
 
-            $testCode();
+            call_user_func($testCode);
         } catch (\Exception $e) {
         } catch (\Throwable $e) {
         }