Description:
------------
SoapClient doesn't seem to clean up after itself when garbage collected. It leaks something around 4K each time. Tested on both Windows and Linux.

Reproduce code:
---------------
<?php
while(true) {
    new SoapClient("test.wsdl");
}
?>


Expected result:
----------------
Assuming that I understand the PHP Garbage Collector (and it's possible that I don't - I'm struggling to find any good documentation on exactly how I should expect it to behave - any pointers very welcome!), I would expect the memory usage of this script to be constant.

Actual result:
--------------
The memory usage increases very quickly (growing to several hundred megabytes in less than a minute).