Simplify the run-command API.
* rs/no-more-run-command-v:
replace and remove run_command_v_opt()
replace and remove run_command_v_opt_cd_env_tr2()
replace and remove run_command_v_opt_tr2()
replace and remove run_command_v_opt_cd_env()
use child_process members "args" and "env" directly
use child_process member "args" instead of string array variable
sequencer: simplify building argument list in do_exec()
bisect--helper: factor out do_bisect_run()
bisect: simplify building "checkout" argument list
am: simplify building "show" argument list
run-command: fix return value comment
merge: remove always-the-same "verbose" arguments
Taylor Blau