Make sure LC_ALL is C.UTF-8 for pytest-postgresql to work
sometimes, different locales make pytest-postgresql hang
Test Plan
tox on a system with LC_ALL=fr_FR.UTF-8
Migrated from D3508 (view on Phabricator)
sometimes, different locales make pytest-postgresql hang
tox on a system with LC_ALL=fr_FR.UTF-8
Migrated from D3508 (view on Phabricator)