pgsql: Dump labels in reproducible order

Dump labels in reproducible order

In pg_get_propgraphdef(), sort the labels before writing out, for a
consistent dump order. Also, since we now have a list, we can get rid
of the separate table scan to get the count.

Co-authored-by: Peter Eisentraut <peter(at)eisentraut(dot)org>
Co-authored-by: Ashutosh Bapat <ashutosh(dot)bapat(dot)oss(at)gmail(dot)com>
Co-authored-by: Andrew Dunstan <andrew(at)dunslane(dot)net>
Reviewed-by: Junwang Zhao <zhjwpku(at)gmail(dot)com>
Reviewed-by: Kirill Reshke <reshkekirill(at)gmail(dot)com>
Discussion: https://www.postgresql.org/message-id/flat/a855795d-e697-4fa5-8698-d20122126567(at)eisentraut(dot)org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/c9babbc8816a4f5d5894eda555e39ba30781322f

Modified Files
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src/backend/utils/adt/ruleutils.c | 59 +++++++++++++++++++++++++++++----------
1 file changed, 44 insertions(+), 15 deletions(-)