[tlbuild] one more time

[Karl Berry]

    Unfortunately, two tests fail on NetBSD/amd64 (they were OK
    yesterday):

    FATAL error while preloading lua module luatex_socket_lua_open(L)+ exit 1
    FAIL luatexdir/luajitimage.test (exit status: 1)

Thanks Marc. I have no idea. Luigi??!!
(Marc's full msg is here: https://tug.org/pipermail/tlbuild/2021q1/004866.html)