Method FileUtil::GetFileStatus() return false when proceesing file which size is bigger than 2^31

[zhanga]

The behavior of system call _wstat in VC9 and VC10 is different when handling file which size is bigger than 2^{31. In VC9, it returns 0. But in VC10, it returns -1. Then some checks will be failed when opening a big file. To fix this issue, we need to use _wstat64 instead of _wstat.}