pgsql: Change PostgresNode::connect_fails() to never send down queries

Change PostgresNode::connect_fails() to never send down queries

This type of failure is similar to what has been fixed in c757a3da,
where an authentication failure combined with psql pushing a command
down its communication pipe causes a test failure.  This routine is
designed to fail, so sending a query has little sense anyway.

Per buildfarm members gaur and hoverfly, based on an analysis and fix
from Tom Lane.

Discussion: https://postgr.es/m/513200.1617634642@sss.pgh.pa.us

Branch
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master

Details
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https://git.postgresql.org/pg/commitdiff/6d41dd045ada28ee14182112fc4cf50fb3879d28

Modified Files
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src/test/perl/PostgresNode.pm | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)