Merge "libfs_avb: Allow overriding the slot suffix." into main am: 30b1c4dd3b

Original change: https://android-review.googlesource.com/c/platform/system/core/+/2587226

Change-Id: I88647c162a1bdf4ec3bcf9564ffc6fa2b60ec762
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>