Merge branch 'mr/bisect-in-c-3'

Rewriting "git bisect" in C continues.

* mr/bisect-in-c-3:
  bisect--helper: retire `--bisect-autostart` subcommand
  bisect--helper: retire `--write-terms` subcommand
  bisect--helper: retire `--check-expected-revs` subcommand
  bisect--helper: reimplement `bisect_state` & `bisect_head` shell functions in C
  bisect--helper: retire `--next-all` subcommand
  bisect--helper: retire `--bisect-clean-state` subcommand
  bisect--helper: finish porting `bisect_start()` to C

diff --cc builtin/bisect--helper.c
Simple merge

diff --cc git-bisect.sh
Simple merge