fix: Fixes in hasntable

hashtable.c

@@ -137,9 +137,10 @@ void hashtable_destroy_bucket(hashtable h, int i)
 {
 	struct entry *e = h->table[i];
 	while (e != NULL) {
+		struct entry *next = e->next;
 		free((void*)e->key);
-		e = e->next;
 		free(e);
+		e = next;
 	}
 }
 
@@ -177,6 +178,9 @@ bool ht_iter_next(ht_iterator *iter)
 		}
 		if (iter->entry == NULL) {
 			iter->index++;
+			if (iter->index >= h->size) {
+				return false;
+			}
 			iter->entry = h->table[iter->index];
 		} else {
 			iter->entry = iter->entry->next;