This fixes an eval error that occurred on hydra with the small channel
and the `nixos.tests.boot.biosCdrom.x86_64-linux` attribute:
> $ nix-instantiate nixos/release-small.nix -A nixos.tests.boot.biosCdrom.x86_64-linux
> warning: unknown setting 'experimental-features'
> error: The option `virtualisation.qemu' does not exist. Definition values:
> - In `/home/andi/dev/nixos/nixpkgs/nixos/modules/testing/test-instrumentation.nix':
> {
> consoles = [ ];
> package = {
> _type = "override";
> content = <derivation /nix/store/q72h2cdcb9zjgiay5gdgzwddjkbjr7xq-qemu-host-cpu-only-for-vm-tests-5.1.0.drv>;
> ...
> (use '--show-trace' to show detailed location information)
In bc2188b we changed test test-instrumentation to also set the QEMU
package that is being used. That change unfortunately caused us to
always assing values to the virtualisation.qemu.package option even when
the option is not defined. The original code was explicitly testing for
the consoles case but the then newly extended version did not adjust the
check as the intention was probably not clear.
With this commit we are always ensuring the entire virtualisation.qemu
section exists and can thus drop the individual tests for each of the
sections since the QEMU module always defines both the package and the
consoles option when it's root is defined..
The vscode-extensions set is already marked as recurseIntoAttrs, but
this has no effect, since this set is two layers deep instead of the
usual one which recurseIntoAttrs applies to.
By applying recurseIntoAttrs to all publishers, the extensions will be
considered by nix tools when listing packages.
