core_test: adjust upstream DateTime tests

Drop old test adjustments, we only test DateTime >= 3 nowadays.

Make the condition for test_pickle_old_with_micros_as_float based on
python version for simplicity.

bt5/erp5_core_test/TestTemplateItem/portal_components/test.erp5.testDateUtils.py

@@ -29,6 +29,7 @@
 
 import os
 import unittest
+import six
 
 import zodbpickle.fastpickle as pickle
 from DateTime import DateTime
@@ -340,27 +341,15 @@ def test_suite():
   class DateTimeTests(test_datetime.DateTimeTests):
     testTimezoneNaiveHandling = unittest.expectedFailure(
       test_datetime.DateTimeTests.testTimezoneNaiveHandling)
+    if six.PY3:
       # ERP5 never used the pickle format with micros as float
       # https://github.com/zopefoundation/DateTime/pull/62
       test_pickle_old_with_micros_as_float = unittest.expectedFailure(
         test_datetime.DateTimeTests.test_pickle_old_with_micros_as_float)
 
-    # This test is only in DateTime >= 3
-    if hasattr(test_datetime.DateTimeTests, 'test_intl_format_hyphen'):
     test_intl_format_hyphen = unittest.expectedFailure(
       test_datetime.DateTimeTests.test_intl_format_hyphen)
 
-    # These 3 tests are only in DateTime 2
-    if hasattr(test_datetime.DateTimeTests, 'test_pickle_new_with_micros'):
-      test_pickle_new_with_micros = unittest.expectedFailure(
-        test_datetime.DateTimeTests.test_pickle_new_with_micros)
-    if hasattr(test_datetime.DateTimeTests, 'test_pickle_new_with_tz'):
-      test_pickle_new_with_tz = unittest.expectedFailure(
-        test_datetime.DateTimeTests.test_pickle_new_with_tz)
-    if hasattr(test_datetime.DateTimeTests, 'testLegacyTimezones'):
-      testLegacyTimezones = unittest.expectedFailure(
-        test_datetime.DateTimeTests.testLegacyTimezones)
-
   suite.addTest(unittest.makeSuite(DateTimeTests))
 
   return suite