pgsql: Add PostgreSQL::Test::Cluster::config_data()

Add PostgreSQL::Test::Cluster::config_data()

This is useful to grab some configuration information from a node
already set up, and I personally found two cases for it: pg_upgrade and
a test to emulate check_guc.

Author: Michael Paquier
Discussion: /messages/by-id/20211129030833.GJ17618@telsasoft.com
Discussion: /messages/by-id/YJ8xTmLQkotVLpN5@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/ba15f16107bea8a93edc505f3013cd7df4ac90fc

Modified Files
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src/test/perl/PostgreSQL/Test/Cluster.pm | 25 +++++++++++++++++++++++++
1 file changed, 25 insertions(+)