pgsql: Sort DO_SUBSCRIPTION_REL dump objects independent of OIDs.

Sort DO_SUBSCRIPTION_REL dump objects independent of OIDs.

Commit 0decd5e89db9f5edb9b27351082f0d74aae7a9b6 missed
DO_SUBSCRIPTION_REL, leading to assertion failures. In the unlikely use
case of diffing "pg_dump --binary-upgrade" output, spurious diffs were
possible. As part of fixing that, align the DumpableObject naming and
sort order with DO_PUBLICATION_REL. The overall effect of this commit
is to change sort order from (subname, srsubid) to (rel, subname).
Since DO_SUBSCRIPTION_REL is only for --binary-upgrade, accept that
larger-than-usual dump order change. Back-patch to v17, where commit
9a17be1e244a45a77de25ed2ada246fd34e4557d introduced DO_SUBSCRIPTION_REL.

Reported-by: vignesh C <vignesh21(at)gmail(dot)com>
Author: vignesh C <vignesh21(at)gmail(dot)com>
Discussion: https://postgr.es/m/CALDaNm2x3rd7C0_HjUpJFbxpAqXgm=QtoKfkEWDVA8h+JFpa_w@mail.gmail.com
Backpatch-through: 17

Branch
------
REL_17_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/1cdc07ad5ae5a50443abed871bd304c0836eaa72

Modified Files
--------------
src/bin/pg_dump/pg_dump.c | 10 +++++-----
src/bin/pg_dump/pg_dump_sort.c | 11 +++++++++++
src/bin/pg_upgrade/t/004_subscription.pl | 27 +++++++++++++++++----------
3 files changed, 33 insertions(+), 15 deletions(-)