Implement file absence checks in art_apex_test.py.

This verifies we don't get unexpected libraries on target, and unexpected
binaries on both host and target.

This also adds several missing checks, and renames some function arguments
to better convey their semantics.

Test: art/build/apex/runtests.sh (on taimen (multilib), cuttlefish (arch32)
  and hikey64_only (arch64), successful runs and with missing checks)
Bug: 124293228
Change-Id: I98f7617291434ba6f6625df57ce75f5f0eb088f1