Better errors for pkg/fixnum

pkg/fixnum/test/int_32_test.dart

Index: pkg/fixnum/test/int_32_test.dart
diff --git a/pkg/fixnum/test/int_32_test.dart b/pkg/fixnum/test/int_32_test.dart
index 8ce782482e7ab8ea203f36c7d782181a68020731..9773deb1781e20e532df6f2aa56c1ceef96c2e6e 100644
--- a/pkg/fixnum/test/int_32_test.dart
+++ b/pkg/fixnum/test/int_32_test.dart
@@ -273,8 +273,8 @@ void main() {
       expect(Int32.MIN_VALUE.toSigned(32), Int32.MIN_VALUE);
       expect(Int32.MAX_VALUE.toSigned(31), -Int32.ONE);
       expect(Int32.MIN_VALUE.toSigned(31), Int32.ZERO);
-      expect(() => Int32.ONE.toSigned(0), throws);
-      expect(() => Int32.ONE.toSigned(33), throws);
+      expect(() => Int32.ONE.toSigned(0), throwsRangeError);
+      expect(() => Int32.ONE.toSigned(33), throwsRangeError);
     });
     test("toUnsigned", () {
       expect(Int32.ONE.toUnsigned(1), Int32.ONE);
@@ -283,8 +283,8 @@ void main() {
       expect(Int32.MIN_VALUE.toUnsigned(32), Int32.MIN_VALUE);
       expect(Int32.MAX_VALUE.toUnsigned(31), Int32.MAX_VALUE);
       expect(Int32.MIN_VALUE.toUnsigned(31), Int32.ZERO);
-      expect(() => Int32.ONE.toUnsigned(-1), throws);
-      expect(() => Int32.ONE.toUnsigned(33), throws);
+      expect(() => Int32.ONE.toUnsigned(-1), throwsRangeError);
+      expect(() => Int32.ONE.toUnsigned(33), throwsRangeError);
     });
     test("toDouble", () {
       expect(new Int32(17).toDouble(), same(17.0));