bpo-30584: Fix test_os fails on non-English Windows (#1980)

* Fix bpo-30584

* Adding a comment mentionning the bpo and explaining what is the identifier

* Add Denis Osipov to Misc/ACKS
diff --git a/Misc/ACKS b/Misc/ACKS
index 8a5bf6e..135491d 100644
--- a/Misc/ACKS
+++ b/Misc/ACKS
@@ -1132,6 +1132,7 @@
 Michele Orrù
 Tomáš Orsava
 Oleg Oshmyan
+Denis Osipov
 Denis S. Otkidach
 Peter Otten
 Michael Otteneder