Test TCP connections in CI too

[mzabani]

Previously we only tested Unix Domain sockets in CI, but not TCP. Was I hoping I would be able to run Darwin tests in parallel, I wonder? Or did I run into the bug recently fixed by a contributor? Not sure. In any case, we don't run Darwin tests in parallel because different instances of postgres would compete to listen on the same port (no Nix sandboxing in Darwin), which would make them fail.

After a recent PR, it became clear to me that we lack tests with TCP. So we need to test it in the pipeline as well (also because cancellation requests reuse the connected-to address, so this is not something that only matters as far as "connection is established, everything now behaves the same"!).

In fact, this reproduces the bug the PR above fixes, namely the following error:

       >   To rerun use: --match "/Transaction/Hpgsql.Transaction/withTransaction issues ROLLBACK when the inner action throws a synchronous exception/" --seed 736461944
       >
       >   TransactionSpec.hs:31:3: 
       >   105) Transaction.Hpgsql.Transaction withTransaction lets irrecoverable errors propagate
       >        uncaught exception: IrrecoverableHpgsqlError
       >        IrrecoverableHpgsqlError {hpgsqlDetails = "An inner exception was thrown", innerException = Just user error (Internal error in hpgsql's recvNonBlocking), relatedStatement = Nothing}
       >
       >   To rerun use: --match "/Transaction/Hpgsql.Transaction/withTransaction lets irrecoverable errors propagate/" --seed 736461944