Re: tablecmds: fix bug where index rebuild loses replica identity on partitions

My testing found a name collision scenario in v18:

create schema w1; set search_path = w1;
create table p (id int not null, a int not null) partition by list (id);
create table p1 partition of p for values in (1);
create table p2 partition of p for values in (2);
create index p_idx on only p (a); -- invalid parent: nothing attached
create index tmp on p2 (a);
alter index p_idx attach partition tmp; -- p2 attached, p1 still not
alter index tmp rename to p1_a_idx; -- p2's index holds p1's default name
alter table p alter column a type bigint; -- ERROR: relation
"p1_a_idx" already exists; should work

Also, with the additional split 0003 now deletes a test case added by
0001, is that intentional?