pgsql: Add min and max aggregates for bytea type.

Add min and max aggregates for bytea type.

Similar to a0f1fce80, although we chose to duplicate logic
rather than invoke byteacmp, primarily to avoid repeat detoasting.

Marat Buharov, Aleksander Alekseev

Discussion: https://postgr.es/m/CAPCEVGXiASjodos4P8pgyV7ixfVn-ZgG9YyiRZRbVqbGmfuDyg@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2d24fd942c7010247c5b7b54b416acf7f4592a4e

Modified Files
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doc/src/sgml/func.sgml                   |  4 ++--
src/backend/utils/adt/varlena.c          | 38 ++++++++++++++++++++++++++++++++
src/include/catalog/catversion.h         |  2 +-
src/include/catalog/pg_aggregate.dat     |  6 +++++
src/include/catalog/pg_proc.dat          | 13 +++++++++++
src/test/regress/expected/aggregates.out | 28 ++++++++++++++++++++++-
src/test/regress/expected/opr_sanity.out |  2 ++
src/test/regress/sql/aggregates.sql      | 11 ++++++++-
8 files changed, 99 insertions(+), 5 deletions(-)