chore(zkstack_cli): Remove temporary performance comparison code (#3090)

## What ❔

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Remove temporary performance comparison code.

## Why ❔

<!-- Why are these changes done? What goal do they contribute to? What
are the principles behind them? -->
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iterators are in context about the evolution of repos. -->

## Checklist

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- [x] PR title corresponds to the body of PR (we generate changelog
entries from PRs).
- [x] Tests for the changes have been added / updated.
- [x] Documentation comments have been added / updated.
- [x] Code has been formatted via `zkstack dev fmt` and `zkstack dev
lint`.

.github/workflows/vm-perf-comparison.yml

@@ -49,8 +49,8 @@ jobs:
       - name: run benchmarks on base branch
         shell: bash
         run: |
-          ci_run zkt || ci_run zkstackup -g --local # TODO remove zkt in an upcoming PR
-          ci_run zk_supervisor contracts --system-contracts || ci_run zkstack dev contracts --system-contracts # TODO remove zk_supervisor in an upcoming PR
+          ci_run zkstackup -g --local
+          ci_run zkstack dev contracts --system-contracts
           ci_run cargo bench --package vm-benchmark --bench iai | tee base-iai
           ci_run cargo run --package vm-benchmark --release --bin instruction_counts | tee base-opcodes || touch base-opcodes