pgsql: Choose ports for test servers less likely to result in conflicts

Choose ports for test servers less likely to result in conflicts

If we choose ports in the range typically used for ephemeral ports there
is a danger of encountering a port conflict due to a race condition
between the time we choose the port in a range below that typically used
to allocate ephemeral ports, but higher than the range typically used by
well known services.

Author: Jelte Fenema-Nio, with some editing by me.

Discussion: https://postgr.es/m/d6ee8761-39d1-0033-1afb-d5a57ee056f2@gmail.com

Backpatch to all live branches (12 and up)

Branch
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REL_14_STABLE

Details
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https://git.postgresql.org/pg/commitdiff/b7d3be64e4378ad85e180838912c774825b02b8c

Modified Files
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src/test/perl/PostgresNode.pm | 13 +++++++++++--
1 file changed, 11 insertions(+), 2 deletions(-)