test(tvix/glue): Add a benchmark for firefox outPath

This is nice to test too - it's similar to hello, but runs for a lot
longer (like 7.5 seconds on my laptop) which means we get even better
stats for stuff.

Change-Id: I7935818f10a6d846d446e685b9263a72d7e2aabd
Reviewed-on: https://cl.tvl.fyi/c/depot/+/12061
Tested-by: BuildkiteCI
Reviewed-by: flokli <flokli@flokli.de>
Autosubmit: aspen <root@gws.fyi>

tvix/glue/benches/eval.rs

@@ -71,6 +71,12 @@ fn eval_nixpkgs(c: &mut Criterion) {
             interpret(black_box("(import <nixpkgs> {}).hello.outPath"));
         })
     });
+
+    c.bench_function("firefox outpath", |b| {
+        b.iter(|| {
+            interpret(black_box("(import <nixpkgs> {}).firefox.outPath"));
+        })
+    });
 }
 
 criterion_group!(