pgsql: Remove no-op GiST support functions in the core GiST opclasses.

Remove no-op GiST support functions in the core GiST opclasses.

The preceding patch allowed us to remove useless GiST support functions.
This patch actually does that for all the no-op cases in the core GiST
code. This buys us whatever performance gain is to be had, and more
importantly exercises the preceding patch.

There remain no-op functions in the contrib GiST opclasses, but those
will take more work to remove.

Discussion: https://postgr.es/m/CAJEAwVELVx9gYscpE=Be6iJxvdW5unZ_LkcAaVNSeOwvdwtD=A@mail.gmail.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/2d484f9b058035d41204f2eb8a0a8d2e8ee57b44

Modified Files
--------------
src/backend/access/gist/gistproc.c | 32 ++------------------------------
src/backend/utils/adt/network_gist.c | 12 ++----------
src/backend/utils/adt/rangetypes_gist.c | 29 +++++------------------------
src/backend/utils/adt/tsgistidx.c | 4 ++++
src/backend/utils/adt/tsquery_gist.c | 9 ++++-----
src/include/catalog/catversion.h | 2 +-
src/include/catalog/pg_amproc.h | 11 -----------
src/include/catalog/pg_proc.h | 16 ----------------
src/test/regress/expected/create_am.out | 6 ++----
src/test/regress/sql/create_am.sql | 6 ++----
10 files changed, 22 insertions(+), 105 deletions(-)