Docs: Remove obsolete comment in object cache tests.

The comment mentioned creating two cache objects with a shared cache directory, which was no longer the case.

Follow-up to [5/tests] [170/tests].

See #55646, #55652.

git-svn-id: https://develop.svn.wordpress.org/trunk@53831 602fd350-edb4-49c9-b593-d223f7449a82

tests/phpunit/tests/cache.php

@@ -8,8 +8,6 @@ class Tests_Cache extends WP_UnitTestCase {
 
 	public function set_up() {
 		parent::set_up();
-		// Create two cache objects with a shared cache directory.
-		// This simulates a typical cache situation, two separate requests interacting.
 		$this->cache =& $this->init_cache();
 	}