Reland "Write classes in runtime-generated app image." am: 0f6af5e3b5

Original change: https://android-review.googlesource.com/c/platform/art/+/2404674

Change-Id: I6c6866f1ec336fa39674a81f59bd3e452a977989
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>