tests: rewrite mq.test from match_grep to match_diff

tests: rewrite mq.test from match_grep to match_diff

Unlike the previous edition of the test that was based on match_grep,
the new one is match_diff based and does more rigorous testing.

* tests/mq.c: Include <stdio.h>.
(NAME): New macro.
(main): Use it.  Print expected output.
* tests/mq.expected: Remove.
* tests/Makefile.am (EXTRA_DIST): Remove mq.expected.
* tests/mq.test: Use run_strace_match_diff.