Use `WellKnownClasses` in reflection. am: 343077add4 am: dec4c7f9db

Original change: https://android-review.googlesource.com/c/platform/art/+/2969531

Change-Id: Ic712ed4ec4dd388c686d3126c139fa889107cc7e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>