PHP 8.5: Tests: Fix usage of no-op ReflectionMethod::setAccessible()

Summary:
As of PHP 8.1.0, calling `setAccessible()` has no effect; all properties are accessible by default.

See https://wiki.php.net/rfc/deprecations_php_8_5#deprecate_reflectionsetaccessible and https://www.php.net/manual/en/reflectionproperty.setaccessible.php

Refs T16494

Test Plan: Run `./bin/arc unit --everything` on PHP 8.5

Reviewers: O1 Blessed Committers, mainframe98

Reviewed By: O1 Blessed Committers, mainframe98

Subscribers: tobiaswiese, valerio.bozzolan, Matthew, Cigaryno

Maniphest Tasks: T16494

Differential Revision: https://we.phorge.it/D26746

src/infrastructure/storage/lisk/__tests__/LiskIsolationTestCase.php

···
 
     try {
       $method = new ReflectionMethod($dao, 'establishLiveConnection');
-      $method->setAccessible(true);
+      if (PHP_VERSION_ID < 80100) {
+        $method->setAccessible(true);
+      }
       $method->invoke($dao, 'r');
 
       $this->assertFailure(