Make tests use APKs instead of exploded APKs

Tests would expect parts of the APK to be unzipped and
maintained. Instead, we now decompress the required files
from the test APKs on test setup. This simplifies
test maintenance substantially.

Test: make libandroidfw_tests && libandroidfw_tests --testdata=frameworks/base/libs/androidfw/tests/data
Change-Id: I3d2100af22df913e02401dedcf9842cdb32b2a3b