Resolve conflicts in src/test/regress/sql/triggers.sql

[silent-observer]

Commit ba9f18a added new test, however
commit 0f40a2d modified a line nearby.
Also modify the test for GPDB by adding a separate distribution key column.

[RekGRpth]

with ORCA

diff -I HINT: -I CONTEXT: -I GP_IGNORE: -U3 /home/gpadmin/gpdb_src/src/test/regress/expected/triggers.out /home/gpadmin/gpdb_src/src/test/regress/results/triggers.out
--- /home/gpadmin/gpdb_src/src/test/regress/expected/triggers.out	2026-06-03 16:44:32.047264114 +0000
+++ /home/gpadmin/gpdb_src/src/test/regress/results/triggers.out	2026-06-03 16:44:32.103263863 +0000
@@ -2570,8 +2570,12 @@
 insert into child3 values (42, 'CCC');
 -- update via parent sees parent-format tuples
 update parent set b = b + 1;
+DETAIL:  Failing row contains (CCC, 43).
+ERROR:  new row for relation "child1" violates partition constraint
 -- delete via parent sees parent-format tuples
 delete from parent;
+DETAIL:  Failing row contains (CCC, 42).
+ERROR:  new row for relation "child1" violates partition constraint
 -- insert into parent sees parent-format tuples
 insert into parent values ('AAA', 42);
 insert into parent values ('BBB', 42);
@@ -2603,6 +2607,8 @@
 drop trigger child3_delete_trig on child3;
 ERROR:  trigger "child3_delete_trig" for table "child3" does not exist
 delete from parent;
+DETAIL:  Failing row contains (CCC, 42).
+ERROR:  new row for relation "child1" violates partition constraint
 -- copy into parent sees tuples collected from children even if there
 -- is no transition-table trigger on the children
 copy parent (a, b) from stdin;

fixed by #2644