Better handling for jobs, backquotes, and builtins

[reubeno]

No description provided.

[github-actions]

Test Results

358 tests   341 ✅  2m 24s ⏱️
 59 suites   17 💤
  8 files      0 ❌

Results for commit 3188b13.

[github-actions]

Performance Benchmark Report

Benchmark name	Baseline (ns)	Test/PR (ns)	Delta (ns)	Delta %
expand_one_string	3312 ns	3357 ns	+45 ns	🟠 +1.36%
instantiate_shell	52523 ns	65032 ns	+12509 ns	🟠 +23.82%
instantiate_shell_with_init_scripts	48391946 ns	48235729 ns	-156217 ns	🟢 -0.32%
parse_bash_completion	6629899 ns	6623015 ns	-6884 ns	🟢 -0.10%
parse_sample_script	11014 ns	10896 ns	-118 ns	🟢 -1.07%
run_echo_builtin_command	91276 ns	104099 ns	+12823 ns	🟠 +14.05%
run_one_builtin_command	108672 ns	121407 ns	+12735 ns	🟠 +11.72%
run_one_external_command	1796791 ns	1835663 ns	+38872 ns	🟠 +2.16%
run_one_external_command_directly	1034800 ns	1040279 ns	+5479 ns	🟠 +0.53%

Code Coverage Report

Package	Base Coverage	New Coverage	Difference
cli.src	🟠 73.95%	🟠 73.95%	⚪ 0%
interactive-shell.src	🟢 75.88%	🟢 76.02%	🟢 0.14%
parser.src	🟢 85.86%	🟢 85.88%	🟢 0.02%
shell.src	🟢 80.58%	🟢 81.32%	🟢 0.74%
shell.src.builtins	🟠 67.57%	🟠 69.06%	🟢 1.49%
Overall Coverage	🟢 79.09%	🟢 79.67%	🟢 0.58%

Minimum allowed coverage is 0%, this run produced 79.67%