riscv64: add initial support for ART. am: 4184f23701 am: f3b0634cd9 am: e6c37e029b

Original change: https://android-review.googlesource.com/c/platform/art/+/2402707

Change-Id: I2a92a0a1e0f95f999306b22919c56c861c545f18
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>