pgsql: Add min() and max() aggregates for xid8.

Add min() and max() aggregates for xid8.

Bump catalog version.

Author: Ken Kato
Reviewed-by: Kyotaro Horiguchi, Fujii Masao
Discussion: https://postgr.es/m/47d77b18c44f87f8222c4c7a3e2dee6b@oss.nttdata.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/400fc6b6487ddf16aa82c9d76e5cfbe64d94f660

Modified Files
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doc/src/sgml/func.sgml               |  4 ++--
src/backend/utils/adt/xid.c          | 24 ++++++++++++++++++++++++
src/include/catalog/catversion.h     |  2 +-
src/include/catalog/pg_aggregate.dat |  6 ++++++
src/include/catalog/pg_proc.dat      | 12 ++++++++++++
src/test/regress/expected/xid.out    | 10 +++++++++-
src/test/regress/sql/xid.sql         |  6 +++++-
7 files changed, 59 insertions(+), 5 deletions(-)