Do not fail when loading an APK without dex files. am: 6f915c7388 am: c386b7a47d

Original change: https://android-review.googlesource.com/c/platform/art/+/2421122

Change-Id: Ib48a6f1c813d20bf69e4e2b5e97720706e862e1f
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>