ref-filter: --format=%(raw) support --perl

ref-filter: --format=%(raw) support --perl

Because the perl language can handle binary data correctly,
add the function perl_quote_buf_with_len(), which can specify
the length of the data and prevent the data from being truncated
at '\0' to help `--format="%(raw)"` support `--perl`.

Reviewed-by: Jacob Keller <jacob.keller@gmail.com>
Helped-by: Ævar Arnfjörð Bjarmason <avarab@gmail.com>
Signed-off-by: ZheNing Hu <adlternative@gmail.com>
Signed-off-by: Junio C Hamano <gitster@pobox.com>