Fix resource-apk inclusion

- We used to include the "install" files, but we really should be using
"output" files instead.

- Also supports a new "inst_resource_apk" property, which is another APK
that's loaded as resources of the instrumentation app itself.

Flag: EXEMPT host test change only
Bug: 292141694
Test: m nothing --no-skip-soong-tests
Test: manual test with a local test module change and make sure
    the second apk exists

Change-Id: Ibd3f9d4a1cbc0f805b2294605ae8bc06fdf53b75