ntpath.samefile fails to detect that "A.TXT" and "a.txt" refer to the same file on Windows XP.

Noticed while researching a buildbot failure due to a patch for issue #10684.
diff --git a/Misc/NEWS b/Misc/NEWS
index 827e837..52d1d61 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -83,6 +83,9 @@
 Library
 -------
 
+- ntpath.samefile failed to notice that "a.txt" and "A.TXT" refer to the same
+  file on Windows XP. As noticed in issue #10684.
+
 - Issue #12000: When a SSL certificate has a subjectAltName without any
   dNSName entry, ssl.match_hostname() should use the subject's commonName.
   Patch by Nicolas Bareil.