v6.13.1.0 for z/OS

Fix release system resources endless loop

There are 3 ways we know that we have completed looping through the list.

 1. If the token returned is -1.
 2. If the token returned is equal to 0. This means we have looped through
    and are back to the first item which we skipped over.
 3. If the new token is equal to the previous token. This means we removed all
    items from the list.