Update panic_handler attribute name changed in nightly

test_suite/no_std/src/main.rs

@@ -6,7 +6,7 @@
 // option. This file may not be copied, modified, or distributed
 // except according to those terms.
 
-#![feature(lang_items, start, panic_implementation)]
+#![feature(lang_items, start, panic_handler)]
 #![no_std]
 
 extern crate libc;
@@ -20,7 +20,7 @@ fn start(_argc: isize, _argv: *const *const u8) -> isize {
 #[no_mangle]
 pub extern "C" fn rust_eh_personality() {}
 
-#[panic_implementation]
+#[panic_handler]
 fn panic(_info: &core::panic::PanicInfo) -> ! {
     unsafe {
         libc::abort();