pgsql: Allow pg_read_all_stats to access all stats views again

Allow pg_read_all_stats to access all stats views again

The views pg_stat_progress_* had not gotten the memo that
pg_read_all_stats is supposed to be able to read all statistics. Also
make a pass over all text-returning pg_stat_xyz functions that could
return "insufficient privilege" and make sure they also respect
pg_read_all_status.

Reported-by: Andrey M. Borodin
Reviewed-by: Andrey M. Borodin, Kyotaro Horiguchi
Discussion: https://postgr.es/m/13145F2F-8458-4977-9D2D-7B2E862E5722@yandex-team.ru

Branch
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REL_10_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/d0bb66572e3326b40515cbf62ec11b3339bbf914

Modified Files
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src/backend/utils/adt/pgstatfuncs.c | 23 ++++++++++++-----------
1 file changed, 12 insertions(+), 11 deletions(-)