User-APC's broken

Run the test app apc2.exe to see what's broken. Apc2.exe sets up a waitable
timer (2sec interval) with an apc callback. The APC callback is called 10 times.
On real Windows this works fine. In ROS (Bochs) the callback run 3 times before
ROS hangs. In WmWare the callback run 2 times before ROS hang. When ROS hang,
it uses 100% CPU.