feat(tvix/glue): add nixpkgs eval benchmark

This adds a criterion.rs-based testbench into tvix-glue.

It can be invoked by running `cargo bench` from inside the `tvix-glue`
crate.
`target/criterion/report/index.html` contains nice graphs.
It's able to diff against the previous run, so you can invoke `cargo
bench` before and after a certain change to reason about the impact in
evaluation performance.

Currently, we need to create a bunch of Evaluator resources inside the
benchmark loop itself, which is a bit annoying, as it leaks into the
things we benchmark.

This should become better with b/262.

Fixes b/322.

Change-Id: I91656a308887baa1d459ed54d58baae919a4aaf2
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10245
Autosubmit: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: tazjin <tazjin@tvl.su>

tvix/Cargo.nix

@@ -9840,6 +9840,11 @@ rec {
           }
         ];
         devDependencies = [
+          {
+            name = "criterion";
+            packageId = "criterion";
+            features = [ "html_reports" ];
+          }
           {
             name = "lazy_static";
             packageId = "lazy_static";