bpo-37552: Skip failing tests in strptime/strftime with UCRT version 17763.615 (#14460)

A bug in MSVC UCRT version 17763.615 (which has been fixed in newer versions) is causing test failures in some strptime/strftime tests when the default code page is c65001. This change selectively skips the tests affected by this.
diff --git a/Lib/test/test_time.py b/Lib/test/test_time.py
index f790d43..8d8d31e 100644
--- a/Lib/test/test_time.py
+++ b/Lib/test/test_time.py
@@ -14,6 +14,7 @@
 except ImportError:
     _testcapi = None
 
+from test.support import skip_if_buggy_ucrt_strfptime
 
 # Max year is only limited by the size of C int.
 SIZEOF_INT = sysconfig.get_config_var('SIZEOF_INT') or 4
@@ -250,6 +251,7 @@
             result = time.strftime("%Y %m %d %H %M %S %w %j", (2000,)+(0,)*8)
         self.assertEqual(expected, result)
 
+    @skip_if_buggy_ucrt_strfptime
     def test_strptime(self):
         # Should be able to go round-trip from strftime to strptime without
         # raising an exception.
@@ -672,6 +674,7 @@
 
 
 class TestPytime(unittest.TestCase):
+    @skip_if_buggy_ucrt_strfptime
     @unittest.skipUnless(time._STRUCT_TM_ITEMS == 11, "needs tm_zone support")
     def test_localtime_timezone(self):