server: Make timer id allocation algorithm conform to the Windows one

[Dmitry Timoshkov]

"Uwe Bonnes" <bon at elektron.ikp.physik.tu-darmstadt.de> wrote:

>    Dmitry> Hello, this patch should fix the problem reported in the bug
>    Dmitry> 10343. My test which calls SetTimer in an infinite loop shows
>    Dmitry> that XP starts to allocate timer ids at 0x7fff and goes
>    Dmitry> backwards to 0x101, then restarts from 0x7fff.
> 
> Isn't this worth a test suite case?

As explained in the referenced bug it's not very easy to test this
behaviour.

-- 
Dmitry.