Description:
------------
ReflectionParameter::getDefaultValue() memory leaks with constant.

Test script:
---------------
<?php

define('TEST_CONST', '10');

class Foo {
    public function bar($param = TEST_CONST) {
        return $param;
    }
}

$refl_method = new ReflectionMethod('Foo::bar');

foreach ($refl_method->getParameters() as $param) {
    if ($param->isDefaultValueAvailable()) {
        var_dump($param->getDefaultValue());
    }
}
?>

Expected result:
----------------
string(2) "10"

Actual result:
--------------
string(2) "10"
[Fri Jun  1 14:09:29 2012]  Script:  '/Users/reeze/Opensource/php-src-
5.3/leak.php'
/Users/reeze/Opensource/php-src-5.3/ext/reflection/php_reflection.c(2424) :  
Freeing 0x10C8A69E8 (11 bytes), script=/Users/reeze/Opensource/php-src-
5.3/leak.php
/Users/reeze/Opensource/php-src-5.3/Zend/zend_variables.c(120) : Actual location 
(location was relayed)
=== Total 1 memory leaks detected ===