Fix regression with 64-bit integer support for Intl

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Created by MOE: https://github.com/google/moe
MOE_MIGRATED_REVID=181389890
diff --git a/lib/src/intl/number_format.dart b/lib/src/intl/number_format.dart
index b4dce92..51a04fd 100644
--- a/lib/src/intl/number_format.dart
+++ b/lib/src/intl/number_format.dart
@@ -643,7 +643,7 @@
   /// Used to test if we have exceeded integer limits.
   // TODO(alanknight): Do we have a MaxInt constant we could use instead?
   static final _maxInt = 1 is double ? pow(2, 52) : 1.0e300.floor();
-  static final _maxDigits = (log(_maxInt)/log(10)).floor();
+  static final _maxDigits = (log(_maxInt)/log(10)).ceil();
 
   /// Helpers to check numbers that don't conform to the [num] interface,
   /// e.g. Int64