This machine is significantly faster. Also, drop nixbuild, since the
transfer speed is too slow to make it worth it.
Change-Id: Ic14ef96e03a81dc429e4b4fec961c891dbb4b2b9
Reviewed-on: https://cl.tvl.fyi/c/depot/+/2066
Reviewed-by: glittershark <grfn@gws.fyi>
Tested-by: BuildkiteCI