Add test for REPLICA IDENTITY with a temporal key

You can only use REPLICA IDENTITY USING INDEX with a unique B-tree
index.  This commit just adds a test showing that you cannot use it
with a WITHOUT OVERLAPS index (which is GiST).

Author: Paul A. Jungwirth <pj@illuminatedcomputing.com>
Discussion: https://www.postgresql.org/message-id/3775839b-3f0f-4c8a-ac03-a253222e6a4b%40illuminatedcomputing.com

src/test/regress/expected/without_overlaps.out

@@ -448,6 +448,10 @@ SELECT * FROM tp2 ORDER BY id, valid_at;
 (1 row)
 
 DROP TABLE temporal_partitioned;
+-- ALTER TABLE REPLICA IDENTITY
+-- (should fail)
+ALTER TABLE temporal_rng REPLICA IDENTITY USING INDEX temporal_rng_pk;
+ERROR:  cannot use non-unique index "temporal_rng_pk" as replica identity
 --
 -- test FK dependencies
 --

src/test/regress/sql/without_overlaps.sql

@@ -315,6 +315,10 @@ SELECT * FROM tp1 ORDER BY id, valid_at;
 SELECT * FROM tp2 ORDER BY id, valid_at;
 DROP TABLE temporal_partitioned;
 
+-- ALTER TABLE REPLICA IDENTITY
+-- (should fail)
+ALTER TABLE temporal_rng REPLICA IDENTITY USING INDEX temporal_rng_pk;
+
 --
 -- test FK dependencies
 --