pgsql: Add pg_version() to PostgreSQL::Test::Cluster

Add pg_version() to PostgreSQL::Test::Cluster

_pg_version (version number based on PostgreSQL::Version) is a field
private to Cluster.pm but there was no helper routine to retrieve it
from a Cluster's node. The same is done for install_path, for example,
and the version object becomes handy when writing tests that need
version-specific handling.

Reviewed-by: Andrew Dunstan, Daniel Gustafsson
Discussion: https://postgr.es/m/YoWfoJTc987tsxpV@paquier.xyz

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/b39838889e76274b107935fa8e8951baf0e8b31b

Modified Files
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src/test/perl/PostgreSQL/Test/Cluster.pm | 14 ++++++++++++++
1 file changed, 14 insertions(+)