[Thread] unify synchronous controller API for testing am: 62eac0132d am: d954531a9d

Original change: https://android-review.googlesource.com/c/platform/packages/modules/Connectivity/+/2995697

Change-Id: Idbeee1102f7e0c4e820e6713bd4dbfb5f9a5510c
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>