Add benchmarks for ACVM execution speed

[TomAFrench]

We're moving all Noir benchmarks out of zk_bench (https://github.com/noir-lang/zk_bench/issues/5) so we need to benchmark ACVM execution speeds in this repo. This is needed anyway in order to get feedback on performance regressions on PRs.

[Savio-Sou]

Best to:

• Use the same suite of benchmarking candidates in https://github.com/AztecProtocol/aztec-packages/tree/master/noir/noir-repo/test_programs/benchmarks
• Support running the benchmarks in local environments (i.e. not just on Mainframe), if this is to supersede Noir benchmarks in https://github.com/noir-lang/zk_bench
  • Document steps to run benchmarks locally in README