perf: remove setup operations from microbenchmarks

[reubeno]

This makes no changes to the code-under-analysis; the perf deltas that show in the PR report are due to the changes in the definitions of the benchmarks.

[github-actions]

Test Results

    2 files      9 suites   1m 29s ⏱️
  572 tests   572 ✅ 0 💤 0 ❌
1 130 runs  1 130 ✅ 0 💤 0 ❌

Results for commit 8124f17.

♻️ This comment has been updated with latest results.

[github-actions]

Performance Benchmark Report

Benchmark name	Baseline (μs)	Test/PR (μs)	Delta (μs)	Delta %
expand_one_string	3.52 μs	2.31 μs	-1.21 μs	🟢 -34.39%
for_loop	561998.39 μs	63.28 μs	-561935.11 μs	🟢 -99.99%
instantiate_shell	61.99 μs	61.59 μs	-0.40 μs	⚪ Unchanged
instantiate_shell_with_init_scripts	28666.65 μs	28262.13 μs	-404.53 μs	⚪ Unchanged
parse_bash_completion	2820.16 μs	2850.73 μs	30.57 μs	🟠 +1.08%
parse_sample_script	4.36 μs	4.44 μs	0.08 μs	🟠 +1.88%
run_echo_builtin_command	91.97 μs	22.07 μs	-69.90 μs	⚪ Unchanged
run_one_external_command	1825.26 μs	1901.14 μs	75.89 μs	🟠 +4.16%

Benchmarks removed:

• run_one_external_command_directly
• run_one_builtin_command

Benchmarks added:

• function_call
• eval_arithmetic
• clone_shell_object

Code Coverage Report: Only Changed Files listed

Package	Base Coverage	New Coverage	Difference
brush-shell/src/shell_factory.rs	🔴 34.78%	🔴 39.02%	🟢 4.24%
Overall Coverage	🟢 77.15%	🟢 76.9%	🔴 -0.25%

Minimum allowed coverage is 70%, this run produced 76.9%