Revert tests for drop index concurrently.

src/test/isolation/expected/drop-index-concurrently-1.out

-Parsed test spec with 3 sessions
-
-starting permutation: noseq prepi preps begin explaini explains select2 drop insert2 end2 selecti selects end
-step noseq: SET enable_seqscan = false;
-step prepi: PREPARE getrow_idx AS SELECT * FROM test_dc WHERE data=34;
-step preps: PREPARE getrow_seq AS SELECT * FROM test_dc WHERE data::text=34::text;
-step begin: BEGIN;
-step explaini: EXPLAIN (COSTS OFF) EXECUTE getrow_idx;
-QUERY PLAN     
-
-Index Scan using test_dc_data on test_dc
-  Index Cond: (data = 34)
-step explains: EXPLAIN (COSTS OFF) EXECUTE getrow_seq;
-QUERY PLAN     
-
-Seq Scan on test_dc
-  Filter: ((data)::text = '34'::text)
-step select2: SELECT * FROM test_dc WHERE data=34;
-id             data           
-
-34             34             
-step drop: DROP INDEX CONCURRENTLY test_dc_data; <waiting ...>
-step insert2: INSERT INTO test_dc(data) SELECT * FROM generate_series(1, 100);
-step end2: COMMIT;
-step selecti: EXECUTE getrow_idx;
-id             data           
-
-34             34             
-134            34             
-step selects: EXECUTE getrow_seq;
-id             data           
-
-34             34             
-134            34             
-step end: COMMIT;
-step drop: <... completed>

src/test/isolation/expected/drop-index-concurrently-2.out

-Parsed test spec with 3 sessions
-
-starting permutation: explain drop cancel rollback droptab selecti dropi
-step explain: EXPLAIN (COSTS OFF) SELECT * FROM test_dc WHERE data=34343;
-QUERY PLAN     
-
-Bitmap Heap Scan on test_dc
-  Recheck Cond: (data = 34343)
-  ->  Bitmap Index Scan on test_dc_data
-        Index Cond: (data = 34343)
-step drop: DROP INDEX CONCURRENTLY test_dc_data; <waiting ...>
-step cancel: SELECT pg_cancel_backend(pid) FROM pg_stat_activity WHERE query = 'DROP INDEX CONCURRENTLY test_dc_data;';
-pg_cancel_backend
-
-t              
-step drop: <... completed>
-error in steps cancel drop: ERROR:  canceling statement due to user request
-step rollback: ROLLBACK;
-step droptab: DROP TABLE test_dc;
-step selecti: SELECT indexrelid::regclass, indisvalid, indisready FROM pg_index WHERE indexrelid = 'test_dc_data'::regclass;
-indexrelid     indisvalid     indisready     
-
-test_dc_data   f              f              
-step dropi: DROP INDEX test_dc_data;

src/test/isolation/isolation_schedule

@@ -14,5 +14,3 @@ test: fk-contention
 test: fk-deadlock
 test: fk-deadlock2
 test: eval-plan-qual
-test: drop-index-concurrently-1
-test: drop-index-concurrently-2

src/test/isolation/specs/drop-index-concurrently-1.spec

-setup
-{
-	CREATE TABLE test_dc(id serial primary key, data int);
-	INSERT INTO test_dc(data) SELECT * FROM generate_series(1, 100);
-	CREATE INDEX test_dc_data ON test_dc(data);
-}
-
-teardown
-{
-	DROP TABLE test_dc;
-}
-
-session "s1"
-step "noseq" { SET enable_seqscan = false; }
-step "prepi" { PREPARE getrow_idx AS SELECT * FROM test_dc WHERE data=34; }
-step "preps" { PREPARE getrow_seq AS SELECT * FROM test_dc WHERE data::text=34::text; }
-step "begin" { BEGIN; }
-step "explaini" { EXPLAIN (COSTS OFF) EXECUTE getrow_idx; }
-step "explains" { EXPLAIN (COSTS OFF) EXECUTE getrow_seq; }
-step "selecti" { EXECUTE getrow_idx; }
-step "selects" { EXECUTE getrow_seq; }
-step "end" { COMMIT; }
-
-session "s2"
-setup { BEGIN; }
-step "select2" { SELECT * FROM test_dc WHERE data=34; }
-step "insert2" { INSERT INTO test_dc(data) SELECT * FROM generate_series(1, 100); }
-step "end2" { COMMIT; }
-
-session "s3"
-step "drop" { DROP INDEX CONCURRENTLY test_dc_data; }
-
-permutation "noseq" "prepi" "preps" "begin" "explaini" "explains" "select2" "drop" "insert2" "end2" "selecti" "selects" "end"

src/test/isolation/specs/drop-index-concurrently-2.spec

-setup
-{
-	CREATE TABLE test_dc(id serial primary key, data int);
-	CREATE INDEX test_dc_data ON test_dc(data);
-}
-
-session "s1"
-setup { BEGIN; }
-step "explain" { EXPLAIN (COSTS OFF) SELECT * FROM test_dc WHERE data=34343; }
-step "rollback" { ROLLBACK; }
-step "droptab" { DROP TABLE test_dc; }
-step "selecti" { SELECT indexrelid::regclass, indisvalid, indisready FROM pg_index WHERE indexrelid = 'test_dc_data'::regclass; }
-step "dropi" { DROP INDEX test_dc_data; }
-
-session "s2"
-step "drop" { DROP INDEX CONCURRENTLY test_dc_data; }
-
-session "s3"
-step "cancel" { SELECT pg_cancel_backend(pid) FROM pg_stat_activity WHERE query = 'DROP INDEX CONCURRENTLY test_dc_data;'; }
-
-permutation "explain" "drop" "cancel" "rollback" "droptab" "selecti" "dropi"