feat(tvix): Add script for running benchmarks in Windtunnel

Currently this just uses a Docker container, which is gross but works
fine for now since we don't have the ability to build benchmarks in nix
as of cl/7538

Change-Id: I48e317f44bc2c73533d7663403786a3a37c7952f
Reviewed-on: https://cl.tvl.fyi/c/depot/+/10189
Reviewed-by: flokli <flokli@flokli.de>
Tested-by: BuildkiteCI
Reviewed-by: grfn <grfn@gws.fyi>
Autosubmit: grfn <grfn@gws.fyi>

tvix/scripts/bench.sh

@@ -0,0 +1,10 @@
+#!/usr/bin/env bash
+
+# Benchmark script that runs inside the Windtunnel build agent
+
+set -euo pipefail
+
+echo "Running benchmarks for tvix/eval..."
+cd tvix/eval
+docker run --rm -v "$(pwd):/app" -w /app rust cargo bench
+windtunnel-cli report -f criterion-rust .