Jobset: test `type`-related constraints

Prior to https://github.com/NixOS/hydra/pull/856, the type-related constraints were a bit too loose, allowing some variations that should have been seen as invalid. This commit adds a test (inspired by https://github.com/NixOS/hydra/pull/856#issuecomment-772820929) to ensure these constraints stay unviolated.

Created by  Cole Helbling  on July 19, 2021
LIKQZ4LGLFOQCUKG5G4ZTQACGOQ4PU4PI4BENALETS747YHE5Y2QC
In channels
upstream
main
Change contents