git-status: Test --ignored behavior

git-status: Test --ignored behavior

Test all possible use-cases of git-status "--ignored" with the
"--untracked-files" option with values "normal" and "all":

 - An untracked directory is listed as untracked if it has a mix of
   untracked and ignored files in it.  With -uall, ignored/untracked
   files are listed as ignored/untracked.

 - An untracked directory with only ignored files is listed as
   ignored.  With -uall, all files in the directory are listed.

 - An ignored directory is listed as ignored. With -uall, all files
   in the directory are listed as ignored.

 - An ignored and committed directory is listed as ignored if it has
   untracked files.  With -uall, all untracked files in the
   directory are listed as ignored.

Signed-off-by: Antoine Pelisse <apelisse@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>