SERVER-9580 Fixed problem with sleepmillis() on Windows due to default timer resolution being typically higher than 15ms

All sleepmillis() calls with values lesser than timer resolution will sleep AT LEAST the timer resolution value, making Mongo be really slow on certain use cases. Like when implementing consumer/producer patterns using capped collections to stream objects back and forth
@benety , I'm not sure if we should set it once or the whole app. In fact, I find that too disruptive for the whole operation of the system hijacking that parameter. If Windows has a given default, I think we should honor changing that for the shortest period of time. That's the reason I preferred to implement this using the approach of set the value we need, call Sleep() and get it back to normal.