Fix BF failure introduced in commit 2bf6c9ff71.

Fix BF failure introduced in commit 2bf6c9ff71.

The sequence subscription test switches regress_seq_sub to connect to the
publisher as regress_seq_repl (a non-superuser) when checking behavior
with insufficient sequence privileges but forgot to set up pg_hba.conf to
allow connections from it. The special setup is only needed on Windows
machines that don't use UNIX sockets.

As per buildfarm.

Reported-by: Ajin Cherian <itsajin@gmail.com>
Author: Ayush Tiwari <ayushtiwari.slg01@gmail.com>
Reviewed-by: vignesh C <vignesh21@gmail.com>
Discussion: https://postgr.es/m/CAFPTHDad911HUMkHgD1KZk+WOvTopiBcYf4C_8Fqj1-sZk3xgw@mail.gmail.com