Remove DataFlow module

I'm not convinced that my modified interface is really enough of an improvement
to warrant the change.

clash-testbench.cabal

@@ -15,7 +15,6 @@ cabal-version:       >=1.10
 
 library
   exposed-modules:     Clash.Testbench.TestM,
-                       Clash.Testbench.DataFlow,
                        Clash.Testbench.TraceView,
                        Clash.Testbench.TraceView.Generic,
                        Clash.Testbench.Impure,

src/Clash/Testbench/DataFlow.hs

-{-# LANGUAGE RankNTypes #-}
-{-# LANGUAGE ScopedTypeVariables #-}
-
-module Clash.Testbench.DataFlow where
-
-import Control.DeepSeq
-import Clash.Testbench.TestM
-import Clash.Prelude
-
-testDF :: forall i o dom. (NFData i)
-       => DataFlow dom Bool Bool i o -> [i] -> [o]
-testDF f =
-    toLogList . runTestM dut . go
-  where
-    dut :: Signal dom (Maybe i, Ready o) -> Signal dom (Maybe o, Ready i)
-    dut ins = bundle $ lowerDF' f x' y'
-      where (x', y') = unbundle ins
-
-    logEmission :: Maybe o -> TestM o (Maybe i, Ready o) (Maybe o, Ready i) ()
-    logEmission = maybe (return ()) logIt
-
-    go :: [i] -> TestM o (Maybe i, Ready o) (Maybe o, Ready i) ()
-    go [] = return ()
-    go (x:xs) = do
-        tickUntil (Nothing, Ready) ((== Ready) . snd) >>= logEmission . fst
-        tickUntil (Just x, Ready) ((== Ready) . snd) >>= logEmission . fst
-        go xs