stdenv: aarch64: Update bootstrap tarballs

Hopefully fixes sandboxed build of glibc on aarch64, as discussed on
https://github.com/NixOS/nixpkgs/commit/8bfa9f528c88243578246798c7c2ddde045e0de0.

Picked from the following cross-trunk evaluation:
http://hydra.nixos.org/eval/1341395 based on nixpkgs
commit bb3ef8a9.

build job: http://hydra.nixos.org/build/50125932

(busybox's hash not changing is not a bug!)