pgsql: btree_gist: Merge the last two versions into version 1.8

btree_gist: Merge the last two versions into version 1.8

During the development cycle of v18, btree_gist has been bumped once to
1.8 for the addition of translate_cmptype support functions (originally
7406ab623fee, renamed in 32edf732e8dc). 1.9 has added sortsupport
functions (e4309f73f698).

There is no need for two version bumps in a module for a single major
release of PostgreSQL. This commit unifies both upgrades to a single
SQL script, downgrading btree_gist to 1.8.

Author: Paul A. Jungwirth <pj(at)illuminatedcomputing(dot)com>
Reviewed-by: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Discussion: https://postgr.es/m/13c61807-f702-4afe-9a8d-795e2fd40923@illuminatedcomputing.com
Backpatch-through: 18

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/b41c4308460500f2888aff9f844458915cae1798

Modified Files
--------------
contrib/btree_gist/Makefile | 2 +-
contrib/btree_gist/btree_gist--1.7--1.8.sql | 197 ++++++++++++++++++++++++++++
contrib/btree_gist/btree_gist--1.8--1.9.sql | 197 ----------------------------
contrib/btree_gist/btree_gist.control | 2 +-
contrib/btree_gist/meson.build | 1 -
5 files changed, 199 insertions(+), 200 deletions(-)