user32/tests: Add more intensive tests for SetCursor.

[Daniel Santos]

Hello!  This is a prelude to other cursor patches to follow (both Griswold's & my work).  As requested, I have replaced the __FILE_SPOT with the standard ok_(file,line) mechanism (looks much better to me).  I've removed the windows version checking from tests and last error checking on success, although I have reservations about it (mostly the later).