Description:
------------
If more than one process of the same session is created in the one time,  this processes are executed simultaneously instead of being executed one after another.

Reproduce code:
---------------
<?php
 //For example this script is asked three times simultaneously from the one user, siting on the one session ID
 require_once('db_fns.php'); //requiring mysql functions and connecting to database
 require_once('session.php'); //creating session from MySQL storage
 $sessid = session_id();
 $example = db_query_onerow("SELECT example FROM table WHERE id=1"); //etc the field `example` is "1" by default. So all three times every process has the value "1"
 echo "Example: $example"; //So every time we will get "1"
 $lock = db_query_onerow("SELECT GET_LOCK('database.lock_{$sessid}', 60);"); //Getting lock to test the bug of PHP
 $anotherexample = db_query_onerow("SELECT example FROM table WHERE id=1"); //This Select will be not executed at the one time because of MySQL locks and will give us the right values
 echo "Another Example: $anotherexample"; //At the first time it will be "1" and two other time "0"
 db_query_write("UPDATE table SET example=0 WHERE id=1"); //Setting the field `example` to 0
 $lock = db_query_onerow("SELECT RELEASE_LOCK('database.lock_{$sessid}')"); //Getting lock to test the bug
?>

Expected result:
----------------
Example: 1
Another Example: 1
Example: 0
Another Example: 0
Example: 0
Another Example: 0

Actual result:
--------------
Example: 1
Example: 1
Example: 1
Another Example: 1
Another Example: 0
Another Example: 0