[RFC] mshtml/tests: Fix events test when pointer is on a corner.

[Nicolas Le Cam]

Hi,

Since commit 8272ecd3f2235b923f2ec67bb51d051bdfbf466f I'm having
errors on events tests.

I just found that it only fails if pointer is on any corner. As I'm
always putting it on upper right corner when running winetest it was
always failing for me.

Minimizing the test window fixed it for me but I'm not sure it's the
right fix, so I'm sending it to wine-devel.
Tested on Win2k SP4 and WinXP SP2 (both with IE6).