[comctl32/tests #3] Use GetModuleHandleA instead of LoadLibraryA

[Mikołaj Zalewski]

> If LoadLibrary is indeed needed it should be accompanied with a 
> FreeLibrary and we probably need a comment for the why as well.

  Does it matter if we call FreeLibrary on the library we are testing? I 
don't think we will be able to free it before the end of the tests when 
anyhow it will be unloaded by the process shutdown. But maybe I should 
care more about elegant code?

Mikolaj Zalewski