comctl32/tests: Added first TaskDialog test.

[Patrick Gauthier]

> Hey, Patrick.
> 
> Look at tests/listview.c for example to see how I load version 6 with
> activation context API. It doesn't work for some reason for XP SP3 (a
> glitch I don't understand), but works fine for everything else. All
> you need is v6util.h.
> 
> Without version 6 activation this test is useless to run in auto mode,
> it will never find TaskDialog entry points.
> 
> Thanks for your interest.

Thanks for the information. I have redone my patch using it.

I looked at v6util.h and could not help but notice two things though:

- There is no need to set processorArchitecture to "x86" or "amd64"
  as far as I know, Windows will happily take "*" to mean "whatever
  the currently applicable architecture is".
- As a result of the previous comment, there would be no point to
  generate the manifest as a file, as it could be loaded from a
  resource (CreateActCtx supports this), that would seem cleaner to me
  than generating temporary files.

- Patrick