[gc] add a pointer to the associated TT for the line I commented out

git-svn-id: https://svn.parrot.org/parrot/trunk@40800 d31e2699-5ff4-0310-a27c-f18f2fbe73fe

src/pmc/scheduler.pmc

@@ -246,8 +246,9 @@ Frees the scheduler's underlying struct.
 */
     VTABLE void destroy() {
         Parrot_Scheduler_attributes * const core_struct = PARROT_SCHEDULER(SELF);
-        /* XXX this line is causing an order-of-destruction error because the scheduler
-           is being freed before it's tasks. Commenting this out till we get a real fix */
+        /* TT #946: this line is causing an order-of-destruction error
+           because the scheduler is being freed before it's tasks.
+           Commenting this out till we get a real fix (although it's a hack) */
         /* MUTEX_DESTROY(core_struct->msg_lock); */
     }