Fix vuln OSV-2024-380

Author: oss-patch

src/H5FL.c

@@ -1199,6 +1199,9 @@ H5FL__blk_gc_list(H5FL_blk_head_t *head)
             /* Get the pointer to the next node */
             next = list->next;
 
+            if (!next) {
+                break;
+            }
             /* Free the block */
             H5MM_free(list);