Don't throw exception for non-integer args to fixnum int32,int64 op ==

pkg/fixnum/test/int_64_test.dart

 // Copyright (c) 2012, the Dart project authors.  Please see the AUTHORS file
 // for details. All rights reserved. Use of this source code is governed by a
 // BSD-style license that can be found in the LICENSE file.
 
 library int64test;
 import 'package:fixnum/fixnum.dart';
 import 'package:unittest/unittest.dart';
 
 void main() {
   group("arithmetic operators", () {
@@ skipping 238 matching lines @@
     test("==", () {
       expect(new int64.fromInt(10) == new int64.fromInt(11), false);
       expect(new int64.fromInt(10) == new int64.fromInt(10), true);
       expect(new int64.fromInt(12) == new int64.fromInt(11), false);
       expect(new int64.fromInt(-10) == new int64.fromInt(-10), true);
       expect(new int64.fromInt(-10) != new int64.fromInt(-10), false);
       expect(largePos == largePos, true);
       expect(largePos == largePosPlusOne, false);
       expect(largePosPlusOne == largePos, false);
       expect(int64.MIN_VALUE == int64.MAX_VALUE, false);
+      expect(new int64.fromInt(17) == new Object(), false);
       expect(new int64.fromInt(17) == null, false);
     });
 
     test(">=", () {
       expect(new int64.fromInt(10) >= new int64.fromInt(11), false);
       expect(new int64.fromInt(10) >= new int64.fromInt(10), true);
       expect(new int64.fromInt(12) >= new int64.fromInt(11), true);
       expect(new int64.fromInt(-10) >= new int64.fromInt(-11), true);
       expect(new int64.fromInt(-10) >= new int64.fromInt(-10), true);
       expect(largePos >= largeNeg, true);
@@ skipping 305 matching lines @@
       expect(int64.MAX_VALUE.toRadixString(10), "9223372036854775807");
       expect(int64.MAX_VALUE.toRadixString(11), "1728002635214590697");
       expect(int64.MAX_VALUE.toRadixString(12), "41A792678515120367");
       expect(int64.MAX_VALUE.toRadixString(13), "10B269549075433C37");
       expect(int64.MAX_VALUE.toRadixString(14), "4340724C6C71DC7A7");
       expect(int64.MAX_VALUE.toRadixString(15), "160E2AD3246366807");
       expect(int64.MAX_VALUE.toRadixString(16), "7FFFFFFFFFFFFFFF");
     });
   });
 }