If our win32 monotonic timers are not monotonic, make them so.

There's a rumor that sometimes GetTickCount64 or GetTickCount can move backwards. This is possibly due to a misunderstanding of bug legacy/trac#23558 (moved) (fixed with 77cc97cf0a20ed0a062a1cb87bef6c40941e4cff). But in case it isn't, we should fix it.

(QueryPerformanceCounter can move backwards, and we have code to handle that.)

Putting this ticket in tor:unspecified since I don't actually think we have a bug here.