libsnapshot: Fix vts_libsnapshot_test.SnapshotUpdateTest#FullUpdateFlow am: 299717115e am: 4327290387

Original change: https://googleplex-android-review.googlesource.com/c/platform/system/core/+/19263115

Change-Id: I595a57d227bdcbf5adb4676c6e188efc48e0dad2
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>