aarch64: update bootstrap-files

fixes #112086

Fetch bootstrap files built by Hydra and re-add them as FODs to skip
currently dangling URLs. They are already available on
https://cache.nixos.org

https://hydra.nixos.org/job/nixpkgs/cross-trunk/bootstrapTools.aarch64.bootstrapFiles.bootstrapTools ->
https://hydra.nixos.org/build/160236233#tabs-details
https://hydra.nixos.org/job/nixpkgs/cross-trunk/bootstrapTools.aarch64.bootstrapFiles.busybox ->
https://hydra.nixos.org/build/160236429#tabs-details

These commands have been run to get the output hashes as FODs:

nix store add-file --name bootstrap-tools.tar.xz  $(nix-store -r /nix/store/ng2xdavskgqxas6b3n76sn0cay15iyhc-bootstrap-tools.tar.xz
--option binary-caches https://cache.nixos.org)
nix store add-path --name busybox $(nix-store -r /nix/store/nhzdjh7nh0ggkbgxh7mhw5fmzq0jxaby-busybox --option binary-caches https://cache.nixos.org)

pkgs/stdenv/linux/bootstrap-files/aarch64.nix

@@ -1,11 +1,11 @@
 {
   busybox = import <nix/fetchurl.nix> {
-    url = "http://tarballs.nixos.org/stdenv-linux/aarch64/bb3ef8a95c9659596b8a34d27881cd30ffea2f9f/busybox";
-    sha256 = "12qcml1l67skpjhfjwy7gr10nc86gqcwjmz9ggp7knss8gq8pv7f";
+    url = "http://tarballs.nixos.org/stdenv-linux/aarch64/571cbf3d1db477058303cef8754fb85a14e90eb7/busybox";
+    sha256 = "sha256-4EN2vLvXUkelZZR2eKaAQA5kCEuHNvRZN6dcohxVY+c=";
     executable = true;
   };
   bootstrapTools = import <nix/fetchurl.nix> {
-    url = "http://tarballs.nixos.org/stdenv-linux/aarch64/c5aabb0d603e2c1ea05f5a93b3be82437f5ebf31/bootstrap-tools.tar.xz";
-    sha256 = "d3f1bf2a1495b97f45359d5623bdb1f8eb75db43d3bf2059fc127b210f059358";
+    url = "http://tarballs.nixos.org/stdenv-linux/aarch64/571cbf3d1db477058303cef8754fb85a14e90eb7/bootstrap-tools.tar.xz";
+    sha256 = "005221ba2eb3f1d890cc6c924ddd79dafab8dbc8a124481e62e9635be35ce829";
   };
 }