further improve panic_immediate_abort by removing rtprintpanic messages

Author: klensy

std/src/rt.rs

@@ -32,9 +32,14 @@ use crate::{mem, panic, sys};
 // - nothing (so this macro is a no-op)
 macro_rules! rtprintpanic {
     ($($t:tt)*) => {
+        #[cfg(not(feature = "panic_immediate_abort"))]
         if let Some(mut out) = crate::sys::stdio::panic_output() {
             let _ = crate::io::Write::write_fmt(&mut out, format_args!($($t)*));
         }
+        #[cfg(feature = "panic_immediate_abort")]
+        {
+            let _ = format_args!($($t)*);
+        }
     }
 }