vmTools.runInLinuxVM: create fd symlinks in /dev
vmTools.runInLinuxVM: create fd symlinks in /dev

These are usually set up by systemd, but there's no systemd in the
VM.  /dev/fd is required for <(...) syntax in bash, and I'm sure lots
of things depend on the stdin/stdout/stderr links as well.

NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs,NixOS/nixpkgs