Add a test for the basic operations on a test that's flaking in a very odd way

pkg/intl/test/date_time_format_test_core.dart

Index: pkg/intl/test/date_time_format_test_core.dart
diff --git a/pkg/intl/test/date_time_format_test_core.dart b/pkg/intl/test/date_time_format_test_core.dart
index 5d3909010c079e1c5fbd7180ec4e120ada6d99b1..65461e2e069bb8a125d61804ee60508591fe6e51 100644
--- a/pkg/intl/test/date_time_format_test_core.dart
+++ b/pkg/intl/test/date_time_format_test_core.dart
@@ -423,4 +423,18 @@ void runDateTests(Function subsetFunc) {
     var aDate = new DateTime(2012, 4, 27, 13, 58, 59, 012);
     expect(f.format(aDate), "118");
   });
+
+  // There are some very odd off-by-one bugs when parsing dates. Put in
+  // some very basic tests to try and get more information.
+  test('Simple Date Creation', () {
+    var format = new DateFormat(DateFormat.NUM_MONTH);
+    var first = format.parse("7");
+    var second = format.parse("7");
+    var basic = new DateTime(1970, 7);
+    var basicAgain = new DateTime(1970, 7);
+    expect(first, second);
+    expect(first, basic);
+    expect(basic, basicAgain);
+    expect(first.month, 7);

[kustermann, 2013/12/10 07:12:22]

I would do it in a loop, to increase the probability of hitting it.

+  });
 }