Merge branch 'ab/various-leak-fixes'

Merge branch 'ab/various-leak-fixes'

Leak fixes.

* ab/various-leak-fixes:
  push: free_refs() the "local_refs" in set_refspecs()
  push: refactor refspec_append_mapped() for subsequent leak-fix
  receive-pack: release the linked "struct command *" list
  grep API: plug memory leaks by freeing "header_list"
  grep.c: refactor free_grep_patterns()
  builtin/merge.c: free "&buf" on "Your local changes..." error
  builtin/merge.c: use fixed strings, not "strbuf", fix leak
  show-branch: free() allocated "head" before return
  commit-graph: fix a parse_options_concat() leak
  http-backend.c: fix cmd_main() memory leak, refactor reg{exec,free}()
  http-backend.c: fix "dir" and "cmd_arg" leaks in cmd_main()
  worktree: fix a trivial leak in prune_worktrees()
  repack: fix leaks on error with "goto cleanup"
  name-rev: don't xstrdup() an already dup'd string
  various: add missing clear_pathspec(), fix leaks
  clone: use free() instead of UNLEAK()
  commit-graph: use free_commit_graph() instead of UNLEAK()
  bundle.c: don't leak the "args" in the "struct child_process"
  tests: mark tests as passing with SANITIZE=leak