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