nix develop should ignore output checks in general.
This was done only for the old way of specifying output checks, the
structured attrs way requires rewriting the JSON and removing the output
checks pieces.
We take a brutal approach of removing as many as possible including
non-recommended ways of doing it.
Fixes #997.
Change-Id: Iaf83029016c71b5171e56e15d4eadc1a60a8be98
Signed-off-by: Raito Bezarius <raito@lix.systems>
(cherry picked from commit 992c3ae981)