ghc: Update containers submodule

Also update a few tests, since containers now has IsList instances.
Signed-off-by: Austin Seipp <austin@well-typed.com>

containers @ e84c5d21

-Subproject commit e787f05e7ef7b07363bd04962af8b1ec65693888
+Subproject commit e84c5d2145415cb0beacce0909a551ae5e28d396

testsuite/tests/overloadedlists/should_run/overloadedlistsrun02.hs

@@ -6,8 +6,3 @@ import GHC.Exts
 main = do print ([] :: (S.Set Int))
           print (['a','b','c'] :: (S.Set Char))
           print (['a','c'..'g'] :: (S.Set Char))
-          
-instance Ord a => IsList (S.Set a) where
- type (Item (S.Set a)) = a
- fromList = S.fromList
- toList = S.toList

testsuite/tests/overloadedlists/should_run/overloadedlistsrun04.hs

@@ -3,10 +3,10 @@
 import qualified Data.Set as S
 import GHC.Exts
 
-main = do putStrLn (f [])       
-          putStrLn (f [1,2])    
-          putStrLn (f [2,0])    
-          putStrLn (f [3,2])     
+main = do putStrLn (f [])
+          putStrLn (f [1,2])
+          putStrLn (f [2,0])
+          putStrLn (f [3,2])
           putStrLn (f [2,7])
           putStrLn (f [2,2])
           putStrLn (f [1..7])
@@ -18,11 +18,3 @@ f [_] = "one element"
 f [2,_] = "two elements, the smaller one is 2"
 f [_,2] = "two elements, the bigger one is 2"
 f _ = "else"
-
-          
-instance Ord a => IsList (S.Set a) where
- type (Item (S.Set a)) = a
- fromList = S.fromList
- toList = S.toList
-          
-