Unrolled build for #146344

Rollup merge of #146344 - Gelbpunkt:loongarch-codegen-llvm-test, r=Mark-Simulacrum

tests/codegen-llvm: Make rust-abi-arch-specific-adjustment portable

This test currently only runs on RISC-V and loongarch hosts, but assumes that the host target is the -gnu target. By using minicore, we can run this test on all host targets, regardless of architecture, as long as the LLVM components are built.
This also fixes this test on musl hosts of these architectures (though I've only tested on loongarch64-unknown-linux-musl).

Author: rust-timer

tests/codegen-llvm/rust-abi-arch-specific-adjustment.rs

@@ -1,15 +1,19 @@
+//@ add-core-stubs
 //@ compile-flags: -Copt-level=3 -C no-prepopulate-passes
 //@ revisions: riscv64 loongarch64
 
-//@[riscv64] only-riscv64
 //@[riscv64] compile-flags: --target riscv64gc-unknown-linux-gnu
 //@[riscv64] needs-llvm-components: riscv
 
-//@[loongarch64] only-loongarch64
 //@[loongarch64] compile-flags: --target loongarch64-unknown-linux-gnu
 //@[loongarch64] needs-llvm-components: loongarch
 
 #![crate_type = "lib"]
+#![feature(no_core)]
+#![no_core]
+
+extern crate minicore;
+use minicore::*;
 
 #[no_mangle]
 // riscv64:     define noundef i8 @arg_attr_u8(i8 noundef zeroext %x)