ART: Move target APEX checks

Move testing and printing from runtests.sh to art_apex_test.py.
Add previously missed target-debug-only checks. Add runtests.sh
debugfs check/building. Remove guestfs code.

Test: art/build/apex/runtests.sh
Test: art/build/apex/runtests.sh -l
Test: art/build/apex/runtests.sh -t
Change-Id: Id0485a090d190ed7a1c3103b7edf01c1dc28e0ed