file_stat() and Stdio->stat() return different values on Win

Imported from http://bugzilla.roxen.com/bugzilla/show_bug.cgi?id=3250

Reported by Jonas Wallden jonasw@roxen.com

> file_stat("c:/jonasw/server-3.3.28/modules/sitebuilder/insite-files/i-
images/pdf.gif")->mtime;
Result: 1016457206
>
> Stdio.File("c:/jonasw/server-3.3.28/modules/sitebuilder/insite-files/i-
images/pdf.gif", "r")->stat()->mtime;
Result: 1016453606

The offset is 3600 seconds.