Fix broken aarch64 unwind test

Author: nbdd0121

tests/ui/asm/aarch64/may_unwind.rs

@@ -16,7 +16,7 @@ impl Drop for Foo<'_> {
     }
 }
 
-extern "C" fn panicky() {
+extern "C-unwind" fn panicky() {
     resume_unwind(Box::new(()));
 }