pgsql: Add more cross-type comparisons to contrib/btree_gin.

Add more cross-type comparisons to contrib/btree_gin.

Using the just-added infrastructure, extend btree_gin to support
cross-type operators in its other opclasses. All of the cross-type
comparison operators supported by the core btree opclasses for
these datatypes are now available for btree_gin indexes as well.

Author: Tom Lane <tgl(at)sss(dot)pgh(dot)pa(dot)us>
Reviewed-by: Arseniy Mukhin <arseniy(dot)mukhin(dot)dev(at)gmail(dot)com>
Discussion: https://postgr.es/m/262624.1738460652@sss.pgh.pa.us

Branch
------
master

Details
-------
https://git.postgresql.org/pg/commitdiff/fc896821c4448038c5cc678c1aff7349ee850b23

Modified Files
--------------
contrib/btree_gin/btree_gin--1.3--1.4.sql | 88 +++++++
contrib/btree_gin/btree_gin.c | 192 +++++++++++++--
contrib/btree_gin/expected/date.out | 362 +++++++++++++++++++++++++++++
contrib/btree_gin/expected/float4.out | 321 +++++++++++++++++++++++++
contrib/btree_gin/expected/float8.out | 50 ++++
contrib/btree_gin/expected/name.out | 59 +++++
contrib/btree_gin/expected/text.out | 50 ++++
contrib/btree_gin/expected/timestamp.out | 306 +++++++++++++++++++++++-
contrib/btree_gin/expected/timestamptz.out | 111 ++++++++-
contrib/btree_gin/sql/date.sql | 64 +++++
contrib/btree_gin/sql/float4.sql | 53 +++++
contrib/btree_gin/sql/float8.sql | 9 +
contrib/btree_gin/sql/name.sql | 11 +
contrib/btree_gin/sql/text.sql | 9 +
contrib/btree_gin/sql/timestamp.sql | 55 ++++-
contrib/btree_gin/sql/timestamptz.sql | 22 +-
16 files changed, 1725 insertions(+), 37 deletions(-)