Include verbose logs in build output for 'make test' failures
    
    When building in koji or copr and a test fails, the verbose output from
    the tests can be very useful in determining the cause.  Print the output
    from failing tests, borrowing heavily from the upstream code¹ used when
    running tests in Travis CI².
    
    This could be done inline in %check rather than in a separate script.
    The downside is that rpm would include each command invocation of the
    loop in the output, which adds a lot of useless text to the already
    copious build output.
    
    ¹ https://git.kernel.org/pub/scm/git/git.git/plain/ci/print-test-failures.sh
    ² https://travis-ci.org/git/git