Fix Android.bp for libartservice and its tests.

- Define `libartservice_defaults` to allow variants (e.g.,
  debug/non-debug variants).
- Remove `export_include_dirs` and `export_shared_lib_headers` because
  libartservice is a JNI lib, which shouldn't export headers for c++
  code to include.
- Use source code in unit tests.

Bug: 177273468
Test: m com.android.art
Test: atest art_standalone_libartservice_tests
Test: out/host/linux-x86/obj/PACKAGING/art-host-gtest_intermediates/art_libartservice_tests32.xml
Change-Id: Ie8bb94c90a15d1b94cf6c812087a568848b5f9da
1 file changed