authgraph: add parallel session VTS tests am: d42cb6fa69 am: f8acaf60db

Original change: https://android-review.googlesource.com/c/platform/hardware/interfaces/+/2786799

Change-Id: I334d3535bb399d11d1e6d9c3869b7abc73ae347e
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>