Remove unused Arbitrary ModelSnapshot and HasVariables (Action Model a)

Author: locallycompact

hydra-node/test/Hydra/Chain/Direct/TxTraceSpec.hs

@@ -251,11 +251,6 @@ instance Num ModelSnapshot where
       , toDecommit = mempty
       }
 
-instance Arbitrary ModelSnapshot where
-  arbitrary = genericArbitrary
-
-  shrink = genericShrink
-
 data State
   = Open
   | Closed
@@ -453,9 +448,6 @@ instance StateModel Model where
 instance HasVariables Model where
   getAllVariables = mempty
 
-instance HasVariables (Action Model a) where
-  getAllVariables = mempty
-
 deriving instance Eq (Action Model a)
 deriving instance Show (Action Model a)