Rollup merge of rust-lang#83820 - petrochenkov:nolinkargs, r=nagisa

Remove attribute `#[link_args]`

Closes rust-lang#29596

The attribute could always be replaced with `-C link-arg`, but cargo didn't provide a reasonable way to pass such flags to rustc.
Now cargo supports `cargo:rustc-link-arg*` directives in build scripts (https://doc.rust-lang.org/cargo/reference/unstable.html#extra-link-arg), so this attribute can be removed.

tests/ui/crate_level_checks/no_std_main_recursion.rs

@@ -1,8 +1,8 @@
+// compile-flags: -Clink-arg=-nostartfiles
 // ignore-macos
 // ignore-windows
 
-#![feature(lang_items, link_args, start, libc)]
-#![link_args = "-nostartfiles"]
+#![feature(lang_items, start, libc)]
 #![no_std]
 
 use core::panic::PanicInfo;

tests/ui/empty_loop_no_std.rs

@@ -1,9 +1,9 @@
+// compile-flags: -Clink-arg=-nostartfiles
 // ignore-macos
 // ignore-windows
 
 #![warn(clippy::empty_loop)]
-#![feature(lang_items, link_args, start, libc)]
-#![link_args = "-nostartfiles"]
+#![feature(lang_items, start, libc)]
 #![no_std]
 
 use core::panic::PanicInfo;