Description:
------------
file_exists() always returns false for relative URIs when called in a class destructor.

Reproduce code:
---------------
class test {
	public $file = 'index.php';
	
	function checkFile() {
		if(file_exists($this->file)) {
			echo "{$this->file} exists";
		} else {
			echo "{$this->file} doesn't exist";
		}
		echo "\n";
	}

	function __destruct() {
		echo 'test::__destruct() : ';
		$this->checkFile();
		echo 'test::__destruct() : ';
		if(file_exists(__FILE__)) {
			echo __FILE__, ' exists';
		} else {
			echo __FILE__, ' doesn\'t exist';
		}
	}
}

$test = new test;
echo 'test::checkFile() : ';
$test->checkFile();

Expected result:
----------------
test::checkFile() : index.php exists
test::__destruct() : index.php exists
test::__destruct() : C:\xampp\htdocs\templating\index.php exists

Actual result:
--------------
test::checkFile() : index.php exists
test::__destruct() : index.php doesn't exist
test::__destruct() : C:\xampp\htdocs\templating\index.php exists