docker, runtime: remove libc6-dev-i386 dependency
docker, runtime: remove libc6-dev-i386 dependency

We already got rid of this dependency thanks to recent data path work
in [0], so there is no need to keep installing this dependency in the
docker images. The only place where it's still needed is for building
bpftool therefore move it into runtime-build so switch to gcc-multilib
there.

  [0] https://github.com/cilium/cilium/pull/10204

Signed-off-by: Daniel Borkmann <3d0f3b9ddcacec30c4008c5e030e6c13a478cb4f@iogearbox.net>

tklauser/cilium,michi-covalent/cilium,cilium-team/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,cilium/cilium,tgraf/cilium,tgraf/cilium,michi-covalent/cilium,tgraf/cilium,cilium/cilium,tklauser/cilium,cilium/cilium,michi-covalent/cilium,tgraf/cilium,cilium-team/cilium,tklauser/cilium,cilium/cilium,tklauser/cilium,michi-covalent/cilium,tgraf/cilium,tklauser/cilium