Description:
------------
If a prepared query with named parameters has one of the paramteres used more than once, then PHP fails with a realloc failure, without giving any useable error message.

This bug triggers only if called from within a class member function

Reproduce code:
---------------
<?php

  $dsn='pgsql:dbname=xenophile host=localhost port=5432 user=stoty';
  $dbc= new PDO($dsn);
  $dbc->setAttribute(PDO_ATTR_ERRMODE, PDO_ERRMODE_EXCEPTION);
  
  class Crashme {
 
 	public function crashfunction($one, $two) {
 		global $dbc;
		$weight_check_stmt=$dbc->prepare("
		select 
   		(select total_cpu_weight from domain0 where id= :domain0_id) -
   		(select cpu_weight from domain_template where id= :template_id) -
   		sum(cpu_weight)
   		as result 
   		from domain where domain0_id = :domain0_id");
    	$weight_check_stmt->bindParam(":domain0_id", $one);
   		$weight_check_stmt->bindParam(":template_id", $two);
    	$weight_check_stmt->execute();
 	}
  }
  
  $crashclass = new Crashme;
  $crashclass->crashfunction(1,2);
?>


Expected result:
----------------
I exepected to get a meaningfull error message, describing the problem, like I get when the above query is not run from a member function) (like in bug 33886)


Actual result:
--------------
I get this in the http error log:

FATAL:  erealloc():  Unable to allocate 4 bytes