[Thread] unify synchronous controller API for testing am: 62eac0132d am: ae0951bd69

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

Change-Id: If1e83a4e3ae4b4fd1bdc69405beb45ccb7795de8
Signed-off-by: Automerger Merge Worker <android-build-automerger-merge-worker@system.gserviceaccount.com>