os: avoid GetFileInformationByHandleEx call when stat'ing files on Windows
os.Stat and os.Lstat on Windows use GetFileInformationByHandleEx to
retrieve file information for reparse points and files that
GetFileAttributesEx does not handle.
However, GetFileInformationByHandleEx is only necessary for
reparse points, so we can avoid the call for regular files.
With this change we can drop the FAT hack that was added in CL 154377,
as files won't have the FILE_ATTRIBUTE_REPARSE_POINT attribute set
on that file system.
Change-Id: Id18639067a6c3fa1bb2c6706d5b79358c224fe37
Reviewed-on: https://go-review.googlesource.com/c/go/+/566397 Reviewed-by: Carlos Amedee <carlos@golang.org> Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com> Reviewed-by: Bryan Mills <bcmills@google.com>