[Ravenwood] Cleanup JVM workarounds

Remove JVM/ART workarounds in the framework codebase as much as
possible so that we don't need to clean up a huge amount of code when we
eventually switch to ART and use libcore directly.

Bug: 359983716
Flag: EXEMPT host side change only
Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh
Change-Id: I81efeec4303dda507f5d5ad75b6d561034ce96d1