Use `env -i` to very explicitly control exactly which environment variables leak into our tests. This enforces a clean separation of "build environment knobs" versus "test suite knobs".
This also includes a minor tweak to how we handle starting our integration daemon, especially to catch failure to start sooner than failing tests.
Signed-off-by: Andrew "Tianon" Page <admwiggin@gmail.com>
Upstream-commit: ed345fb18ee9d003f30884b696628b75380a426a
Component: engine
f303319a62