internal/syscall/windows: fix ReOpenFile sentinel error value

internal/syscall/windows: fix ReOpenFile sentinel error value

ReOpenFile is documented to return INVALID_HANDLE_VALUE on error,
but the previous definition was checking for 0 instead.

Change-Id: Idec5e75e40b9f6c409e068d63a9b606781e80a46
Reviewed-on: https://go-review.googlesource.com/c/go/+/717320
Auto-Submit: Quim Muntal <quimmuntal@gmail.com>
LUCI-TryBot-Result: Go LUCI <golang-scoped@luci-project-accounts.iam.gserviceaccount.com>
Reviewed-by: Damien Neil <dneil@google.com>
Reviewed-by: Alex Brainman <alex.brainman@gmail.com>
Reviewed-by: Michael Pratt <mpratt@google.com>