pgsql: Implement ANY_VALUE aggregate

Implement ANY_VALUE aggregate

SQL:2023 defines an ANY_VALUE aggregate whose purpose is to emit an
implementation-dependent (i.e. non-deterministic) value from the
aggregated rows.

Author: Vik Fearing <vik@postgresfriends.org>
Reviewed-by: Peter Eisentraut <peter.eisentraut@enterprisedb.com>
Reviewed-by: David Rowley <dgrowleyml@gmail.com>
Discussion: https://www.postgresql.org/message-id/flat/5cff866c-10a8-d2df-32cb-e9072e6b04a2@postgresfriends.org

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2ddab010c2777c6a965cea82dc1b809ddc33ecc1

Modified Files
--------------
doc/src/sgml/func.sgml                   | 14 ++++++++++++++
src/backend/catalog/sql_features.txt     |  1 +
src/backend/utils/adt/misc.c             |  9 +++++++++
src/include/catalog/catversion.h         |  2 +-
src/include/catalog/pg_aggregate.dat     |  4 ++++
src/include/catalog/pg_proc.dat          |  8 ++++++++
src/test/regress/expected/aggregates.out | 30 ++++++++++++++++++++++++++++++
src/test/regress/sql/aggregates.sql      |  7 +++++++
8 files changed, 74 insertions(+), 1 deletion(-)