shell32/tests: Avoid casts from a COM object to an iface.

[Michael Stefaniuc]

On 06/29/2016 10:02 AM, Marvin wrote:
> Hi,
> 
> While running your changed tests on Windows, I think I found new failures.
> Being a bot and all I'm not very good at pattern recognition, so I might be
> wrong, but could you please double-check?
> Full results can be found at
> https://testbot.winehq.org/JobDetails.pl?Key=23879
> 
> Your paranoid android.
> 
> 
> === w1064 (32 bit shlfolder) ===
> shlfolder.c:1591: Test failed: IShellFolder_GetDisplayNameOf(NULL) failed! hr = 80070057
> 
> === w1064 (64 bit shlfolder) ===
> shlfolder.c:1591: Test failed: IShellFolder_GetDisplayNameOf(NULL) failed! hr = 80070057
This is a pre-existing failure.

bye
	michael