Separate handling of a single path and a list of paths when determining am: 8701bf5f32 am: 7146ae6961

Original change: https://android-review.googlesource.com/c/platform/art/+/2962584

Change-Id: I67e10ed0e27bc10bcd66436195f140e45adb376b
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>