OK, somehow, although all of the ALLEGRO variants specify that we should be using buildi.exe or build.exe, when we actually get to test-program, it's using alisp.exe, which seems to cause breakage.
I am looking at the output of ALL-ALLEGRO-VARIANTS.
So what is crushing the allegro executable and invoking something else?
Looks like it's (LISP-IMPLEMENTATION-ENVIRONMENT-VARIABLE implementation), which crushes the use of LISP-IMPLEMENTATION-IDENTIFIERS.
If I simply crush the lines in run-tests.sh that re-exports ALLEGRO, that fixes the tests on allegro.
I have pushed that fix.
Need to retest....