bpo-29097: Forego fold detection on windows for low timestamp values (GH-2385)

bpo-29097: Forego fold detection on windows for low timestamp values (GH-2385)

On Windows, passing a negative value to local results in an OSError because localtime_s on Windows does not support negative timestamps. Unfortunately this means that fold detection for timestamps between 0 and max_fold_seconds will result in this OSError since we subtract max_fold_seconds from the timestamp to detect a fold. However, since we know there haven't been any folds in the interval [0, max_fold_seconds) in any timezone, we can hackily just forego fold detection for this time range on Windows.