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

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