pgsql: Add SQL function array_reverse()

Add SQL function array_reverse()

This function takes in input an array, and reverses the position of all
its elements.  This operation only affects the first dimension of the
array, like array_shuffle().

The implementation structure is inspired by array_shuffle(), with a
subroutine called array_reverse_n() that may come in handy in the
future, should more functions able to reverse portions of arrays be
introduced.

Bump catalog version.

Author: Aleksander Alekseev
Reviewed-by: Ashutosh Bapat, Tom Lane, Vladlen Popolitov
Discussion: https://postgr.es/m/CAJ7c6TMpeO_ke+QGOaAx9xdJuxa7r=49-anMh3G5476e3CX1CA@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/49d6c7d8dabad8c59ba21afe72ff32e79f822291

Modified Files
--------------
doc/src/sgml/func.sgml                  |  17 +++++
src/backend/utils/adt/array_userfuncs.c | 112 ++++++++++++++++++++++++++++++++
src/include/catalog/catversion.h        |   2 +-
src/include/catalog/pg_proc.dat         |   3 +
src/test/regress/expected/arrays.out    |  31 +++++++++
src/test/regress/sql/arrays.sql         |   7 ++
6 files changed, 171 insertions(+), 1 deletion(-)