pgsql: amcheck: Add a GIN index to the CREATE INDEX CONCURRENTLY tests

amcheck: Add a GIN index to the CREATE INDEX CONCURRENTLY tests

The existing CREATE INDEX CONCURRENTLY tests checking only B-Tree, but
can be cheaply extended to also check GIN. This helps increasing test
coverage for GIN amcheck, especially related to handling concurrent page
splits and posting list trees.

This already helped to identify several issues during development of the
GIN amcheck support.

Author: Mark Dilger <mark.dilger@enterprisedb.com>
Reviewed-By: Tomas Vondra <tomas.vondra@enterprisedb.com>
Reviewed-By: Kirill Reshke <reshkekirill@gmail.com>
Discussion: https://postgr.es/m/BC221A56-977C-418E-A1B8-9EFC881D80C5%40enterprisedb.com

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/68f97aeadb8e50794addaf5c1f8e9a67f75691b8

Modified Files
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contrib/amcheck/t/002_cic.pl     | 10 +++++++---
contrib/amcheck/t/003_cic_2pc.pl | 40 +++++++++++++++++++++++++++++++++-------
2 files changed, 40 insertions(+), 10 deletions(-)