Make art_test_common_defaults inherit art_defaults.

To take art_defaults closer to a true global defaults used by
everything in the ART module. This also means we unify the compiler
flags for various test-only things that didn't inherit art_defaults
explicitly.

Also some code cleanups in tests that were uncovered by the extra
compiler warnings.

#codehealth

Test: Run-tests, gtests, libcore tests and libjdwp tests for host and
  device on master-art
Test: mmm art/libnativeloader/
Bug: 204364566
Change-Id: I618881ca618c32c40f26b4d354f48d5f9c42fc12
4 files changed