Added test for swapping uniqye keys without pk

localtests/swap-uk-uk/create.sql

@@ -0,0 +1,24 @@
+drop table if exists gh_ost_test;
+create table gh_ost_test (
+  id bigint,
+  i int not null,
+  ts timestamp(6),
+  unique key id_uidx(id),
+  unique key its_uidx(i, ts)
+) ;
+
+drop event if exists gh_ost_test;
+delimiter ;;
+create event gh_ost_test
+  on schedule every 1 second
+  starts current_timestamp
+  ends current_timestamp + interval 60 second
+  on completion not preserve
+  enable
+  do
+begin
+  insert into gh_ost_test values ((unix_timestamp() << 2) + 0, 11, now(6));
+  insert into gh_ost_test values ((unix_timestamp() << 2) + 1, 13, now(6));
+  insert into gh_ost_test values ((unix_timestamp() << 2) + 2, 17, now(6));
+  insert into gh_ost_test values ((unix_timestamp() << 2) + 3, 19, now(6));
+end ;;

localtests/swap-uk-uk/extra_args

@@ -0,0 +1 @@
+--alter="drop key id_uidx, drop key its_uidx, add unique key its2_uidx(i, ts), add unique key id2_uidx(id)" 

localtests/swap-uk-uk/order_by

@@ -0,0 +1 @@
+id