Fix the obscure corner case of three items in a plural

pkg/intl/lib/intl.dart

Index: pkg/intl/lib/intl.dart
diff --git a/pkg/intl/lib/intl.dart b/pkg/intl/lib/intl.dart
index 281d2fdc6f53ef22016bf3895e9743dcd7f68a96..871fdc903aad7903873fa6c6d1d33001f8186c87 100644
--- a/pkg/intl/lib/intl.dart
+++ b/pkg/intl/lib/intl.dart
@@ -269,7 +269,7 @@ class Intl {
       case 1 : return (one == null) ? other : one;
       case 2: return (two == null) ? ((few == null) ? other : few) : two;
       default:
-        if (howMany == 3 || howMany == 4 && few != null) return few;
+        if ((howMany == 3 || howMany == 4) && few != null) return few;
         if (howMany > 10 && howMany < 100 && many != null) return many;
         return other;
     }