Implement #7566 - os.path.sameopenfile for Windows.

This uses the GetFileInformationByHandle function to return a tuple of values
to identify a file, then ntpath.sameopenfile compares file tuples, which
is exposed as os.path.sameopenfile.
diff --git a/Misc/NEWS b/Misc/NEWS
index 732c145..1ac1dec 100644
--- a/Misc/NEWS
+++ b/Misc/NEWS
@@ -13,6 +13,8 @@
 Library
 -------
 
+- Issue #7566: Implement os.path.sameopenfile for Windows.
+
 - Issue #9293: I/O streams now raise ``io.UnsupportedOperation`` when an
   unsupported operation is attempted (for example, writing to a file open
   only for reading).