Optimizer trace support for multi-table UPDATE and DELETE

create table ten(a int);

insert into ten values (0),(1),(2),(3),(4),(5),(6),(7),(8),(9);

create table t10 (a int, b int);

insert into t10 select a,a from ten;

alter table t10 add key(a);

create table t11 like t10;

insert into t11 select * from t10;

explain delete t10,t11 from t10, t11 where t10.a=t11.a and t11.a<3;

select * from information_schema.optimizer_trace\G