Merge branch 'rs/no-more-run-command-v'

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