Use compile_multilib: "both" with "32"/"64" suffixes by default for ART am: 12143d53f2 am: de2b100eb1

Original change: https://android-review.googlesource.com/c/platform/art/+/2122595

Change-Id: I1d75176aa7bf322f867e292c5d3f3dd601f3a71b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>