advapi32/tests: Test for last error after RegQueryValueEx

[Nikolay Sivov]

Before failing showing property panel with unimplemented urlmon stub Word 2007
does query for some registry key checking for last error after it. Key isn't found
in this case and last error is ERROR_SUCCESS, check doesn't fail in Wine
cause we don't touch last error and Word reset it to zero before calling RegQueryValueEx.

This test is to keep in mind that fact.