Use <windows.h> and "wine/test.h" in test cases for better portabiliy.

[Mike McCormack]

Francois Gouget wrote:

> Including each header manually surely is not normal practice on Windows, 
> but the nice thing is that it lets us detect bugs in our header 
> dependencies. If we just include windows.h we will completely miss those 
> and thus reduces the value of the test.

These tests don't compile in MSVC 6 without this fix.

Mike