fix(l1, l2): cargo test compilation at workspace level

[ilitteri]

Motivation

cargo test at the workspace level or in cmd/ethrex is not compiling. This is because ethrex-l2-rpc is a dev-dependencie.

This issue uncovered a bigger issue, that is the existence of benches inside cmd/ethrex.

Description

This PR solves the compilation error by moving benchmarks to a separate crate, benches. It also removes an unsued benchmark.

[Copilot]

Pull Request Overview

Fix cargo test compilation by moving benchmarks out of cmd/ethrex into a dedicated benches crate and updating related paths and CI.

• Move bench targets from cmd/ethrex to a new benches crate and remove the unused import_blocks benchmark
• Update include paths in build_block_benchmark.rs now that it lives under benches
• Add benches to workspace and update the CI workflow to run the benchmark from the new location

Reviewed Changes

Copilot reviewed 6 out of 7 changed files in this pull request and generated 2 comments.

Show a summary per file

File	Description
cmd/ethrex/bench/import_blocks_benchmark.rs	Remove unused benchmark to eliminate dev-dep coupling.
cmd/ethrex/Cargo.toml	Drop bench-related dev-deps and bench targets; formatting tweaks for features.
benches/benches/build_block_benchmark.rs	Adjust include paths to fixtures after relocating the bench into its own crate.
benches/Cargo.toml	New crate for benchmarks, with dev-deps and bench target configuration.
Cargo.toml	Add benches crate to the workspace members.
.github/workflows/pr_perf_build_block_bench.yml	Update benchmark workflow working directory to the new crate (note: see comment below).

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[Copilot]

cwd should point to the crate root (where Cargo.toml resides). The benches crate root is benches, not benches/benches. Update to cwd: 'benches' so cargo bench runs correctly.

Suggested change

	cwd: "benches/benches"
	cwd: "benches"

[Copilot]

std::fs::exists does not exist. Use std::fs::try_exists(&storage_path).unwrap_or(false) or Path::new(&storage_path).exists().

Suggested change

	if std::fs::exists(&storage_path).unwrap_or(false) {
	if storage_path.path().exists() {

[github-actions]

Lines of code report

Total lines added: 232
Total lines removed: 0
Total lines changed: 232

Detailed view

+-------------------------------------------------+-------+------+
| File                                            | Lines | Diff |
+-------------------------------------------------+-------+------+
| ethrex/benches/benches/build_block_benchmark.rs | 232   | +232 |
+-------------------------------------------------+-------+------+