Parsed test spec with 4 sessions

starting permutation: d1a1 d2a2 e1l e2l d1a2 d2a1 d1c e1c d2c e2c
step d1a1: SELECT lock_share(1,x), lock_excl(3,x) FROM bigt LIMIT 1;
lock_share|lock_excl
----------+---------
         1|        1
(1 row)

step d2a2: select lock_share(2,x) FROM bigt LIMIT 1;
lock_share
----------
         1
(1 row)

step e1l: SELECT lock_excl(1,x) FROM bigt LIMIT 1; <waiting ...>
step e2l: SELECT lock_excl(2,x) FROM bigt LIMIT 1; <waiting ...>
step d1a2: SET debug_parallel_query = on;
			  SET parallel_setup_cost = 0;
			  SET parallel_tuple_cost = 0;
			  SET min_parallel_table_scan_size = 0;
			  SET parallel_leader_participation = off;
			  SET max_parallel_workers_per_gather = 3;
			  SELECT sum(lock_share(2,x)) FROM bigt; <waiting ...>
step d2a1: SET debug_parallel_query = on;
			  SET parallel_setup_cost = 0;
			  SET parallel_tuple_cost = 0;
			  SET min_parallel_table_scan_size = 0;
			  SET parallel_leader_participation = off;
			  SET max_parallel_workers_per_gather = 3;
			  SELECT sum(lock_share(1,x)) FROM bigt;
			  SET debug_parallel_query = off;
			  RESET parallel_setup_cost;
			  RESET parallel_tuple_cost;
			  SELECT lock_share(3,x) FROM bigt LIMIT 1; <waiting ...>
step d1a2: <... completed>
  sum
-----
10000
(1 row)

step d1c: COMMIT;
step e1l: <... completed>
lock_excl
---------
        1
(1 row)

step d2a1: <... completed>
  sum
-----
10000
(1 row)

lock_share
----------
         1
(1 row)

step e1c: COMMIT;
step d2c: COMMIT;
step e2l: <... completed>
lock_excl
---------
        1
(1 row)

step e2c: COMMIT;