wintrust(3/3): Fix a couple tests on a variety of systems

[Juan Lang]

Hi Paul,

> This is of course on boxes where people dont' run winetest as a
> administrator. I'm not sure if ERROR_ACCESS_DENIED is thus actually an
> acceptable failure. In other tests we have used skip() for this.

Of course that's the reason, but not running as administrator is an
acceptable configuration, is it not?  I use skip() where subsequent
tests will fail as a result of an early failure, but that wasn't the
case here.
--Juan