This is the first in a set of patches to add AAP as an experimental target to LLVM. The only changes this patch makes is to recognize the 'aap' triple.
Future patches will incrementally add the remainder of the backend.
LGTM. The target triple is added everywhere appropriate and the tests are sensible. It's a minor annoyance that the relevant enum and case statements are inconsistent about whether they're in alphabetic order or order of addition of that backend, but that's not AAP's fault and your additions are in sensible places.