Use u32 methods instead of manual shifting

Switch to `to_be_bytes()` and `from_be_bytes()` instead of manual
shifting

This was suggested [`here`](rust-lang#105145 (comment))

Signed-off-by: Ayush Singh <[email protected]>

Author: Ayush1325

src/tools/remote-test-server/src/main.rs

@@ -365,13 +365,7 @@ fn my_copy(src: &mut dyn Read, which: u8, dst: &Mutex<dyn Write>) {
     loop {
         let n = t!(src.read(&mut b));
         let mut dst = dst.lock().unwrap();
-        t!(dst.write_all(&[
-            which,
-            (n >> 24) as u8,
-            (n >> 16) as u8,
-            (n >> 8) as u8,
-            (n >> 0) as u8,
-        ]));
+        t!(dst.write_all(&create_header(which, n as u32)));
         if n > 0 {
             t!(dst.write_all(&b[..n]));
         } else {
@@ -383,19 +377,21 @@ fn my_copy(src: &mut dyn Read, which: u8, dst: &Mutex<dyn Write>) {
 fn batch_copy(buf: &[u8], which: u8, dst: &Mutex<dyn Write>) {
     let n = buf.len();
     let mut dst = dst.lock().unwrap();
-    t!(dst.write_all(&[which, (n >> 24) as u8, (n >> 16) as u8, (n >> 8) as u8, (n >> 0) as u8,]));
+    t!(dst.write_all(&create_header(which, n as u32)));
     if n > 0 {
         t!(dst.write_all(buf));
         // Marking buf finished
         t!(dst.write_all(&[which, 0, 0, 0, 0,]));
     }
 }
 
+const fn create_header(which: u8, n: u32) -> [u8; 5] {
+    let bytes = n.to_be_bytes();
+    [which, bytes[0], bytes[1], bytes[2], bytes[3]]
+}
+
 fn read_u32(r: &mut dyn Read) -> u32 {
     let mut len = [0; 4];
     t!(r.read_exact(&mut len));
-    ((len[0] as u32) << 24)
-        | ((len[1] as u32) << 16)
-        | ((len[2] as u32) << 8)
-        | ((len[3] as u32) << 0)
+    u32::from_be_bytes(len)
 }