user32/tests: Use SetRect instead of open coding it.

[Michael Stefaniuc]

On 04/18/2016 10:50 AM, Marvin wrote:
> 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=22284
> 
> Your paranoid android.
> 
> 
> === w8 (32 bit sysparams) ===
> sysparams.c:2485: Test failed: Waiting for the WM_DISPLAYCHANGE message timed out
> sysparams.c:2496: Test failed: Set bpp 32, but WM_DISPLAYCHANGE reported bpp -1
> 
> === w864 (32 bit sysparams) ===
> sysparams.c:2485: Test failed: Waiting for the WM_DISPLAYCHANGE message timed out
> sysparams.c:2496: Test failed: Set bpp 32, but WM_DISPLAYCHANGE reported bpp -1
Unrelated as even a whitespace diff produces them:
https://testbot.winehq.org/JobDetails.pl?Key=22288

bye
	michael