By: Tom Sydney Kerckhove <syd@cs-syd.eu>
Enable tests for sydtest-persistent-postgresql and sydtest-sqitch{,-persistent}
Tests were disabled with doCheck = false. The comment on
sydtest-persistent-postgresql framed it as a workaround for an
older-nixpkgs glibc issue (with a question mark even at the time);
neither sqitch override had any comment. All three pass on current
nixpkgs, including the per-package test suites.
Disabling these tests upstream meant any regression in the test
helpers we expose for sqitch+persistent integration would only
surface in downstream consumers.