MDEV-8133 ALTER TABLE can perform the operation but escape the binary log

fix a few cases where a successful ALTER was not binlogged:
* on errors after the completed ALTER, binlog it, then return an error
* don't let thd->killed abort open_table() after completed
  online ALTER.

sql/sql_table.cc

@@ -6889,7 +6889,7 @@ static bool mysql_inplace_alter_table(THD *thd,
                                       MDL_request *target_mdl_request,
                                       Alter_table_ctx *alter_ctx)
 {
-  Open_table_context ot_ctx(thd, MYSQL_OPEN_REOPEN);
+  Open_table_context ot_ctx(thd, MYSQL_OPEN_REOPEN | MYSQL_OPEN_IGNORE_KILLED);
   handlerton *db_type= table->s->db_type();
   MDL_ticket *mdl_ticket= table->mdl_ticket;
   HA_CREATE_INFO *create_info= ha_alter_info->create_info;
@@ -9094,13 +9094,13 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
       error, but still worth reporting as it might indicate serious
       problem with server.
     */
-    goto err_with_mdl;
+    goto err_with_mdl_after_alter;
   }
 
 end_inplace:
 
   if (thd->locked_tables_list.reopen_tables(thd))
-    goto err_with_mdl;
+    goto err_with_mdl_after_alter;
 
   THD_STAGE_INFO(thd, stage_end);
 
@@ -9199,6 +9199,10 @@ bool mysql_alter_table(THD *thd,char *new_db, char *new_name,
 
   DBUG_RETURN(true);
 
+err_with_mdl_after_alter:
+  /* the table was altered. binlog the operation */
+  write_bin_log(thd, true, thd->query(), thd->query_length());
+
 err_with_mdl:
   /*
     An error happened while we were holding exclusive name metadata lock