Partially revert "Insert temporary debugging output in regression tests."

This reverts much of commit f03a9ca4,
but leaves the relpages/reltuples probe in select_parallel.sql.
The pg_stat_all_tables probes are unstable enough to be annoying,
and it no longer seems likely that they will teach us anything more
about the underlying problem.  I'd still like some more confirmation
though that the observed plan instability is caused by VACUUM leaving
relpages/reltuples as zero for one of these tables.

Discussion: https://postgr.es/m/CA+hUKG+0CxrKRWRMf5ymN3gm+BECHna2B-q1w8onKBep4HasUw@mail.gmail.com

src/test/regress/expected/select_parallel.out

@@ -103,19 +103,6 @@ where relname like '__star' order by relname;
  f_star  |        1 |        16
 (6 rows)
 
-select relname, vacuum_count, analyze_count, autovacuum_count, autoanalyze_count
-from pg_stat_all_tables
-where relname like '__star' order by relname;
- relname | vacuum_count | analyze_count | autovacuum_count | autoanalyze_count 
----------+--------------+---------------+------------------+-------------------
- a_star  |            1 |             0 |                0 |                 0
- b_star  |            1 |             0 |                0 |                 0
- c_star  |            1 |             0 |                0 |                 0
- d_star  |            1 |             0 |                0 |                 0
- e_star  |            1 |             0 |                0 |                 0
- f_star  |            1 |             0 |                0 |                 0
-(6 rows)
-
 -- Disable Parallel Append
 alter table a_star reset (parallel_workers);
 alter table b_star reset (parallel_workers);

src/test/regress/expected/stats.out

@@ -199,33 +199,6 @@ FROM prevstats AS pr;
  t
 (1 row)
 
--- Temporary hack to investigate whether extra vacuum/analyze is happening
-select relname, relpages, reltuples
-from pg_class
-where relname like '__star' order by relname;
- relname | relpages | reltuples 
----------+----------+-----------
- a_star  |        1 |         3
- b_star  |        1 |         4
- c_star  |        1 |         4
- d_star  |        1 |        16
- e_star  |        1 |         7
- f_star  |        1 |        16
-(6 rows)
-
-select relname, vacuum_count, analyze_count, autovacuum_count, autoanalyze_count
-from pg_stat_all_tables
-where relname like '__star' order by relname;
- relname | vacuum_count | analyze_count | autovacuum_count | autoanalyze_count 
----------+--------------+---------------+------------------+-------------------
- a_star  |            1 |             0 |                0 |                 0
- b_star  |            1 |             0 |                0 |                 0
- c_star  |            1 |             0 |                0 |                 0
- d_star  |            1 |             0 |                0 |                 0
- e_star  |            1 |             0 |                0 |                 0
- f_star  |            1 |             0 |                0 |                 0
-(6 rows)
-
 DROP TABLE trunc_stats_test, trunc_stats_test1, trunc_stats_test2, trunc_stats_test3, trunc_stats_test4;
 DROP TABLE prevstats;
 -- End of Stats Test

src/test/regress/sql/select_parallel.sql

@@ -40,9 +40,6 @@ select round(avg(aa)), sum(aa) from a_star a3;
 select relname, relpages, reltuples
 from pg_class
 where relname like '__star' order by relname;
-select relname, vacuum_count, analyze_count, autovacuum_count, autoanalyze_count
-from pg_stat_all_tables
-where relname like '__star' order by relname;
 
 -- Disable Parallel Append
 alter table a_star reset (parallel_workers);

src/test/regress/sql/stats.sql

@@ -174,14 +174,6 @@ SELECT st.heap_blks_read + st.heap_blks_hit >= pr.heap_blks + cl.relpages,
 SELECT pr.snap_ts < pg_stat_get_snapshot_timestamp() as snapshot_newer
 FROM prevstats AS pr;
 
--- Temporary hack to investigate whether extra vacuum/analyze is happening
-select relname, relpages, reltuples
-from pg_class
-where relname like '__star' order by relname;
-select relname, vacuum_count, analyze_count, autovacuum_count, autoanalyze_count
-from pg_stat_all_tables
-where relname like '__star' order by relname;
-
 DROP TABLE trunc_stats_test, trunc_stats_test1, trunc_stats_test2, trunc_stats_test3, trunc_stats_test4;
 DROP TABLE prevstats;
 -- End of Stats Test