I have a fix for test-sysdef-asdf that I have checked in in 3.1.6.17.
Briefly, the test previously used a call out with RUN-PROGRAM to find the build script's notion of what the set of files in ASDF is, and then compare that with what's in asdf.asd. I couldn't get that to run for me.
I replaced the call out using RUN-PROGRAM with some lisp code that does the same task.
Please LMK if that works now.