Tweak parallel hash join test case in hopes of improving stability.

This seems to make things better on gaur, let's see what the rest
of the buildfarm thinks.

Thomas Munro

Discussion: https://postgr.es/m/CAEepm=1uuT8iJxMEsR=jL+3zEi87DB2v0+0H9o_rUXXCZPZT3A@mail.gmail.com

src/test/regress/expected/join.out

@@ -6073,7 +6073,7 @@ rollback to settings;
 -- parallel with parallel-aware hash join
 savepoint settings;
 set local max_parallel_workers_per_gather = 2;
-set local work_mem = '128kB';
+set local work_mem = '192kB';
 set local enable_parallel_hash = on;
 explain (costs off)
   select count(*) from simple r join simple s using (id);

src/test/regress/sql/join.sql

@@ -2116,7 +2116,7 @@ rollback to settings;
 -- parallel with parallel-aware hash join
 savepoint settings;
 set local max_parallel_workers_per_gather = 2;
-set local work_mem = '128kB';
+set local work_mem = '192kB';
 set local enable_parallel_hash = on;
 explain (costs off)
   select count(*) from simple r join simple s using (id);