Test fixes and rebase conflicts, round 2

Conflicts:
	src/libcore/num/mod.rs

src/libstd/fs.rs

@@ -946,7 +946,7 @@ mod tests {
             let mut read_stream = check!(File::open(filename));
             let mut read_buf = [0; 1028];
             let read_str = match check!(read_stream.read(&mut read_buf)) {
-                -1|0 => panic!("shouldn't happen"),
+                0 => panic!("shouldn't happen"),
                 n => str::from_utf8(&read_buf[..n]).unwrap().to_string()
             };
             assert_eq!(read_str, message);