minor #279 PimpleTest: Only call setAccessible on PHP < 8.1 (reedy)

This PR was merged into the main branch.

Discussion
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PimpleTest: Only call setAccessible on PHP < 8.1

https://www.php.net/manual/en/reflectionproperty.setaccessible.php

> Note: As of PHP 8.1.0, calling this method has no effect; all properties are accessible by default.

and

> This function has been DEPRECATED as of PHP 8.5.0. Relying on this function is highly discouraged.

Commits
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86c553f PimpleTest: Only call setAccessible on PHP < 8.1

Author: fabpot

src/Pimple/Tests/PimpleTest.php

@@ -275,11 +275,15 @@ public function testExtendDoesNotLeakWithFactories()
         unset($pimple['foo']);
 
         $p = new \ReflectionProperty($pimple, 'values');
-        $p->setAccessible(true);
+        if (PHP_VERSION < 80100) {
+            $p->setAccessible(true);
+        }
         $this->assertEmpty($p->getValue($pimple));
 
         $p = new \ReflectionProperty($pimple, 'factories');
-        $p->setAccessible(true);
+        if (PHP_VERSION < 80100) {
+            $p->setAccessible(true);
+        }
         $this->assertCount(0, $p->getValue($pimple));
     }