[tlbuild] asy-2.85 and TL23 versions

[Karl Berry]

    Looking into the asy changelog [0], John Bowman recommends usage of
    tirpc, so I added libtirpc-dev into my build dependencies (Debian
    Buster) – build works with and without it.

Thanks for noticing (I hadn't). I've now mentioned it at
https://tug.org/texlive/build.html#asymptote.

    it seems the status quo has not caused big troubles as of yet.

Indeed. So if the library is no trouble to provide (just installing the
package), then sure, we might as well. But clearly it's not the end of
the world if it's not present ... --thanks, karl.