Remove duplication

Author: workingjubilee

tests/ui/abi/debug.rs

@@ -7,14 +7,12 @@
 // This pattern is prepared for when we account for alignment in the niche.
 //@ normalize-stderr: "(valid_range): [1-9]\.\.=(429496729[0-9]|1844674407370955161[0-9])" -> "$1: $$NON_NULL"
 // Some attributes are only computed for release builds:
-//@ add-core-stubs
 //@ compile-flags: -O
 //@ revisions: generic riscv64
 //@ [riscv64] only-riscv64
 //@ [generic] ignore-riscv64
 
-#![feature(rustc_attrs,no_core)]
-#![no_core]
+#![feature(rustc_attrs)]
 #![crate_type = "lib"]
 #![feature(no_core)]
 #![no_std]
@@ -23,7 +21,6 @@
 extern crate minicore;
 use minicore::*;
 
-extern crate minicore;
 struct S(u16);
 
 #[rustc_abi(debug)]