t1517: more coverage for commands that work without repository

t1517: more coverage for commands that work without repository

While most of the commands in Git suite are designed to do useful
things in Git repositories, some commands are also usable outside
any repository.  Building on top of an earlier work abece6e9 (t1517:
test commands that are designed to be run outside repository,
2024-05-20) that adds tests for such commands, let's give coverage
to some more commands.

This patch covers commands whose code has hits for

    $ git grep setup_git_directory_gently

and passes a pointer to nongit_ok variable it uses to allow it to
run outside a Git repository, but mostly they are tested only to see
that they start up (as opposed to dying with "not in a git
repository" complaint).  We may want to update them to actually do
something useful later, but this would at least help us catch
regressions by mistake.

Signed-off-by: Junio C Hamano <gitster@pobox.com>