Use the new perf_record hook to only include perf in the benchmarking code

[mdboom]

This uses the perf_record hook in pyperf by @mpage to only collect Linux perf data in actual benchmarking code.

Cc: @mpage

[Copilot]

PR Overview

This PR updates the benchmarking code to leverage the new perf_record hook so that Linux perf data is only collected when needed. Key changes include:

• Adding a helper function (has_any_element) in bench_runner/util.py to check iterables.
• Refactoring run_benchmarks in bench_runner/scripts/run_benchmarks.py to remove the command_prefix parameter and integrate the new perf_record hook.
• Updating related templates and dependency versions to support the new perf_record functionality.

Reviewed Changes

File	Description
bench_runner/util.py	Added has_any_element helper to check iterables safely.
bench_runner/scripts/run_benchmarks.py	Removed command_prefix, introduced get_perf_lines, updated PERF handling and perf_to_csv functions.
bench_runner/templates/_benchmark.src.yml	Modified system tuning command to handle perf resetting when enabled.
bench_runner/templates/env.yml	Updated the PYPERFORMANCE_HASH value.
pyproject.toml	Bumped pyperf version from 2.8.1 to 2.9.0.

Copilot reviewed 5 out of 5 changed files in this pull request and generated 1 comment.