feat(tvix/eval): Implement comparison for lists

Lists are compared lexicographically in C++ nix as of [0], and our
updated nix test suites depend on this. This implements comparison of
list values in `Value::nix_cmp` using a very similar algorithm to what
C++ does - similarly to there, this requires passing in the VM so we can
force thunks in the list elements as we go.

[0]: 09471d2680#

Change-Id: I5d8bb07f90647a1fec83f775243e21af856afbb1
Reviewed-on: https://cl.tvl.fyi/c/depot/+/7070
Autosubmit: grfn <grfn@gws.fyi>
Reviewed-by: sterni <sternenseemann@systemli.org>
Tested-by: BuildkiteCI

tvix/eval/src/builtins/mod.rs

@@ -418,7 +418,7 @@ fn pure_builtins() -> Vec<Builtin> {
             &[false, false],
             |args: Vec<Value>, vm: &mut VM| {
                 Ok(Value::Bool(matches!(
-                    args[0].force(vm)?.nix_cmp(&*args[1].force(vm)?)?,
+                    args[0].force(vm)?.nix_cmp(&*args[1].force(vm)?, vm)?,
                     Some(Ordering::Less)
                 )))
             },