Windows ctime should be set to `mtime` if `mtime < ctime`

[Luro02]

The code passes null pointer for the creation time, so it is not changed. (see documentation of SetFileTime)

https://github.com/alexcrichton/filetime/blob/1df0704e39ab951b669f4acc4128db0c7c16863e/src/windows.rs#L34-L54

With this, it is possible to change modified time to a time earlier than the created time, which does not make sense:

//# filetime = "*"

use std::fs;
use std::io;
use std::path::Path;
use std::time::Duration;

use filetime::FileTime;

fn run() -> io::Result<()> {
    let filepath = Path::new("test.abc123");

    // create the example file if it does not exist:
    fs::write(filepath, "hello world")?;

    // query the metadata:
    let metadata = fs::metadata(filepath)?;

    let ctime = FileTime::from(metadata.created()?);
    let mtime = FileTime::from(metadata.modified()?);
    let atime = FileTime::from(metadata.accessed()?);

    println!("ctime: {}, mtime: {}, atime: {}", ctime, mtime, atime,);

    // note: as expected the created time will be the same or
    //       earlier than the last modification time:
    assert_eq!(ctime <= mtime, true);

    let new_time = FileTime::from(metadata.modified()? - Duration::from_secs(60 * 60 * 24));

    filetime::set_file_times(filepath, new_time, new_time)?;

    let metadata = fs::metadata(filepath)?;

    let ctime = FileTime::from(metadata.created()?);
    let mtime = FileTime::from(metadata.modified()?);
    let atime = FileTime::from(metadata.accessed()?);

    println!("ctime: {}, mtime: {}, atime: {}", ctime, mtime, atime,);

    // note: the modified time is now earlier than the created
    //       time, which should not be possible:
    assert_eq!(mtime < ctime, true);

    fs::remove_file(filepath)?;

    Ok(())
}

fn main() {
    run().expect("failed to execute");
}