Merge "libfs_avb: Allow overriding the slot suffix." into main am: 30b1c4dd3b am: 8e60a8d6db am: 1937311500

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

Change-Id: I8fa1134afeb25423d63fc50e1a9632f97794e406
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>