Speculative fix for flaky CallAudioRouteStateMachine tests

Add a wait for handler to make sure that there's no spurious
multithreading

Test: test change
Merged-In: Ic293a8a5b71cca8c218ae276a7298971e14318fc
Change-Id: Ic293a8a5b71cca8c218ae276a7298971e14318fc
1 file changed