bug#24984: Emacs 25.1.1: Problems with file completion in Windows shell

[Ulrich Windl]

I think this bug is new compared to Emacs 24.3:
Shell completion on MS-Windows does not work correctly. For excample:
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Microsoft Windows [Version 6.1.7601]
Copyright (c) 2009 Microsoft Corporation. Alle Rechte vorbehalten.

c:\Windows\system32>cd /Users/Ulrich Windl/
cd /Users/Ulrich Windl/

c:\Users\Ulrich Windl>dir
dir
 Datenträger in Laufwerk C: ist Windows
 Volumeseriennummer: 42BC-2012

 Verzeichnis von c:\Users\Ulrich Windl

17.08.2016  14:10    <DIR>          .
17.08.2016  14:10    <DIR>          ..
04.08.2016  08:21    <DIR>          Application Data
15.03.2016  15:19    <DIR>          Contacts
17.08.2016  14:21    <DIR>          Desktop
18.10.2016  10:21    <DIR>          Documents
22.11.2016  09:49    <DIR>          Downloads
12.10.2016  10:13    <DIR>          Favorites
31.05.2016  12:16    <DIR>          Pictures
20.10.2016  08:23    <DIR>          Videos
               5 Datei(en),          4.542 Bytes
              20 Verzeichnis(se), 184.763.269.120 Bytes frei
---

When I try to complete "cd D", "Documents" is not in the list of possible
matches. Instead I see things that are NOT part of the current directory (but
of c:\Windows\system32), like this:
Possible completions are:
DRVSTORE/       Dism/   DriverStore/
da-DK/  de-DE/  de/
drivers/