Unrolled build for rust-lang#129311

Rollup merge of rust-lang#129311 - onur-ozkan:multiple-candidates-fix, r=Kobzol

don't copy `.rustc-dev-contents` from CI rustc

Since rust-lang#127188, copying files from `.rustc-dev-contents` regressed rust-lang#108767 again. Since `rustc-src` is already included in the CI rustc sysroot, we don't need to copy these files to have `rustc-src` component.

Blocker for rust-lang#122709

src/bootstrap/src/core/build_steps/compile.rs

@@ -1692,16 +1692,8 @@ impl Step for Sysroot {
  build_helper::exit!(1);
  }
 
- // Unlike rust-src component, we have to handle rustc-src a bit differently.
- // When using CI rustc, we copy rustc-src component from its sysroot,
- // otherwise we handle it in a similar way what we do for rust-src above.
- if builder.download_rustc() {
- cp_rustc_component_to_ci_sysroot(
- builder,
- &sysroot,
- builder.config.ci_rustc_dev_contents(),
- );
- } else {
+ // rustc-src component is already part of CI rustc's sysroot
+ if !builder.download_rustc() {
  let sysroot_lib_rustlib_rustcsrc = sysroot.join("lib/rustlib/rustc-src");
  t!(fs::create_dir_all(&sysroot_lib_rustlib_rustcsrc));
  let sysroot_lib_rustlib_rustcsrc_rust = sysroot_lib_rustlib_rustcsrc.join("rust");