Clean Arch Linux image for testing

Concatenate the splits and untar it to use.

# wget or aria2
aria2c -j 10 -x 10 -Z -- https://github.com/pw4ever/linux-kernel-hacking-helper/releases/download/arch-clean/arch-clean.tar.a{a,b,c,d,e,f}
cat arch-clean.tar.* | tar xvf -