libarchive: Make test_read_append_filter_wrong_program pass again

libarchive: Apply upstream commit a1b7bf8013fb7a11a486794247daae592db6f5ae

This fixes the failing test_read_append_filter_wrong_program test in CI
which has been failing since 01-Dec-2020.

Commit message from https://github.com/libarchive/libarchive/commit/a1b7bf8013fb7a11a486794247daae592db6f5ae

Silence stderr in test_read_append_filter_program

When the FreeBSD testsuite runs the libarchive tests it checks that stderr
is empty. Since #1382 this is no longer the case. This change restores
the behaviour of silencing bunzip2 stderr but doesn't bring back the
output text check.

Partially reverts 2e7aa5d9

MFC after: 3 days
Differential Revision: https://reviews.freebsd.org/D29036