Revert "async exception safety for coprocesses"

This reverts commit 7013798df5.

Utility/Exception.hs

@@ -1,6 +1,6 @@
 {- Simple IO exception handling (and some more)
  -
- - Copyright 2011-2020 Joey Hess <id@joeyh.name>
+ - Copyright 2011-2016 Joey Hess <id@joeyh.name>
  -
  - License: BSD-2-clause
  -}
@@ -20,7 +20,6 @@ module Utility.Exception (
 	bracketIO,
 	catchNonAsync,
 	tryNonAsync,
-	catchAsync,
 	tryWhenExists,
 	catchIOErrorType,
 	IOErrorType(..),
@@ -88,14 +87,6 @@ catchNonAsync a onerr = a `catches`
 	, M.Handler (\ (e :: SomeException) -> onerr e)
 	]
 
-{- Catches only async exceptions. -}
-catchAsync :: MonadCatch m => m a -> (Either AsyncException SomeAsyncException -> m a) -> m a
-catchAsync a onerr = a `catches`
-	[ M.Handler (\ (e :: AsyncException) -> onerr (Left e))
-	, M.Handler (\ (e :: SomeAsyncException) -> onerr (Right e))
-	, M.Handler (\ (e :: SomeException) -> throwM e)
-	]
-
 tryNonAsync :: MonadCatch m => m a -> m (Either SomeException a)
 tryNonAsync a = go `catchNonAsync` (return . Left)
   where