Description:
------------
debug_print_backtrace reports wrong class context in a constructor.

Linux version 2.6.7-1.478
PHP 5.0.3RC1 and RC2

Reproduce code:
---------------
 <?php
class a
{
  function __construct () 
    {
      echo ("this is a\n");
      debug_print_backtrace();
    }
}
class b extends a
{
  function __construct () 
    {
      echo ("this is b\n");
      parent::__construct();
    }
}
$x = new b();
?> 


Expected result:
----------------
this is b
this is a
#0  a->__construct() called at [/home/ostri/xulapps/alf/php/cl_test.php:15]
#1  b->__construct() called at [/home/ostri/xulapps/alf/php/cl_test.php:18]


Actual result:
--------------
this is b
this is a
#0  b->__construct() called at [/home/ostri/xulapps/alf/php/cl_test.php:15]
#1  b->__construct() called at [/home/ostri/xulapps/alf/php/cl_test.php:18]