Rename BadNumberFormatException -> FormatException.

utils/tests/pub/pubspec_test.dart

Index: utils/tests/pub/pubspec_test.dart
diff --git a/utils/tests/pub/pubspec_test.dart b/utils/tests/pub/pubspec_test.dart
index 1add34db5886e9f1a9d0fd2166103352e59b46fb..befca24f450256e09dfe370df7775908930161f1 100644
--- a/utils/tests/pub/pubspec_test.dart
+++ b/utils/tests/pub/pubspec_test.dart
@@ -45,13 +45,13 @@ dependencies:
         var sources = new SourceRegistry();
         sources.register(new MockSource());
 
-        throwsBadFormat(() {
+        expect(() {
         new Pubspec.parse('''
 dependencies:
   foo:
     mock: bad
 ''', sources);
-        });
+        }, throwsFormatException);
       });
 
       test("allows comment-only files", () {
@@ -70,7 +70,3 @@ dependencies:
     });
   });
 }
-
-throwsBadFormat(function) {
-  expect(function, throwsA((e) => e is FormatException));
-}