enable atomic yield when delayed_freeing is encountered

src/heap.c

@@ -147,7 +147,7 @@ static void mi_heap_collect_ex(mi_heap_t* heap, mi_collect_t collect)
 
   // collect all pages owned by this thread
   mi_heap_visit_pages(heap, &mi_heap_page_collect, &collect, NULL);
-  mi_assert_internal( collect != ABANDON || heap->thread_delayed_free == NULL );
+  mi_assert_internal( collect != ABANDON || mi_atomic_read_ptr(mi_block_t,&heap->thread_delayed_free) == NULL );
 
   // collect segment caches
   if (collect >= FORCE) {

src/page.c

@@ -130,7 +130,7 @@ void _mi_page_use_delayed_free(mi_page_t* page, mi_delayed_t delay, bool overrid
     tfreex = mi_tf_set_delayed(tfree, delay);
     old_delay = mi_tf_delayed(tfree);
     if (mi_unlikely(old_delay == MI_DELAYED_FREEING)) {
-      // mi_atomic_yield(); // delay until outstanding MI_DELAYED_FREEING are done.
+      mi_atomic_yield(); // delay until outstanding MI_DELAYED_FREEING are done.
       tfree = mi_tf_set_delayed(tfree, MI_NO_DELAYED_FREE); // will cause CAS to busy fail
     }
     else if (delay == old_delay) {