Supporrt tapas build for vector tests

Such that UX team has less pain on building the VD / AVD assets.
This also requires removing internal API dependence in the test.

To build the VectorDrawableTest with prebuilt SDK.
<root dir>/tapas VectorDrawableTest
<root dir>/make -j64 showcommand
Then later for incremental build.
<root dir>/mmm ./frameworks/base/tests/VectorDrawableTest/ -j20

b/18260896

Change-Id: Id559074df78d7c2a5c529c545834da23986bc15f