Make windows sleep consistent with non-windows sleep
Make windows sleep consistent with non-windows sleep

Prior to this commit, we would always only sleep for 1 ms on windows
if yielding was allowed regardless of how much idle time had passed
while on non-windows, we would sleep for larger amounts of time as
more idle time has passed.

This commit changes the logic so that windows and non-windows both
sleep for similar amounts of time as more and more idle time passes.

Praetonus/ponyc,cquinn/ponyc,Theodus/ponyc,sgebbie/ponyc,sgebbie/ponyc,Theodus/ponyc,CausalityLtd/ponyc,cquinn/ponyc,Theodus/ponyc,dipinhora/ponyc,cquinn/ponyc,ponylang/ponyc,kulibali/ponyc,Theodus/ponyc,jemc/ponyc,cquinn/ponyc,sgebbie/ponyc,ponylang/ponyc,dipinhora/ponyc,jemc/ponyc,CausalityLtd/ponyc,kulibali/ponyc,kulibali/ponyc,Theodus/ponyc,sgebbie/ponyc,Praetonus/ponyc,kulibali/ponyc,CausalityLtd/ponyc,dipinhora/ponyc,Praetonus/ponyc,jemc/ponyc,Praetonus/ponyc,sgebbie/ponyc,ponylang/ponyc