Make sure DisabledOnRavenwood on unloadable tests works

Fix: 367694651
Test: $ANDROID_BUILD_TOP/frameworks/base/ravenwood/scripts/run-ravenwood-tests.sh
Test: mkdir -p frameworks/base/packages/SystemUI/multivalentTests/src/com/android/systemui/privacy/ &&
    mv fameworks/base/packages/SystemUI/tests/src/com/android/systemui/privacy/PrivacyDialogControllerTest.kt \
      frameworks/base/packages/SystemUI/multivalentTests/src/com/android/systemui/privacy/ &&
    atest SystemUiRavenTests

Flag: EXEMPT host test change only
Change-Id: If5166537febae5c3af46474a2b65da0b7ea16fec