Looks like this may be due to problems configuring the fasl file locations for the tests. I see this in the transcript:

; Fast loading ; /home/rpg/lisp/asdf/build/fasls/acl/asdf/test/unintern-foo.fasl cfwbi-ufo asdf-test::c => #<excl:fasl-casemode-mismatch @ #x205e0e42> TEST ABORTED: #P"/home/rpg/lisp/asdf/build/fasls/acl/asdf/test/unintern-foo.fasl" was compiled in case-insensitive-upper mode. Continuing to load this file may result in symbol-name mismatches.

Surely the build/fasls/ subdirectories should distinguish between ACL alisp and mlisp.

Perhaps somehow the normal implementation location logic doesn't work in the tests?