Remove use of NumericUnderscores for compatibility

...with GHC 8.2 and 8.4.

Author: sjakobi

tests/Regressions.hs

@@ -1,7 +1,6 @@
 {-# LANGUAGE BinaryLiterals      #-}
 {-# LANGUAGE CPP                 #-}
 {-# LANGUAGE MagicHash           #-}
-{-# LANGUAGE NumericUnderscores  #-}
 {-# LANGUAGE ScopedTypeVariables #-}
 {-# LANGUAGE TypeApplications    #-}
 {-# LANGUAGE UnboxedTuples       #-}
@@ -268,7 +267,7 @@ issue420 = do
 -- Issue 491
 
 issue491 :: TestTree
-issue491 = localOption (mkTimeout 1_000_000) $ testGroup "issue491" $
+issue491 = localOption (mkTimeout 1000000) $ testGroup "issue491" $
     [ testCase "1" $ assert $ m [0, -1] `HML.isSubmapOf` m [0, -1]
     , testCase "2" $ assert $ m [1, 0b11111] `HML.isSubmapOf` m [1, 0b11111]
     , testCase "3" $ assert $ m [1, 0b11111] `HML.isSubmapOf` m [1, 0b11111, 42]