[Ravenwood] Apply a common policy across all code

Some policies should apply to all code processed by hoststubgen
universally, e.g. host side JVM workarounds. Update hoststubgen to
accept multiple policy files, and make sure all existing framework jars
have this universal policy applied.

Flag: EXEMPT host test change only
Bug: 292141694
Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh
Change-Id: Icc0e775b5ba0dd6a09768be8cda4b03cb33522a5