In particular, JVM IR doesn't provide KtFile for a multifile facade in
JvmDeclarationOrigin (JVM backend provides KtFile of a random multifile
part). This led to multifile classes being completely ignored in the
JVM_IR version of kapt. Now they are generated correctly and the changed
test passes, but there's a _ir.txt expectation file because the order of
'foo' and 'bar' is different (which is not a problem).