Add CTS tests for Absolute Volume Control

Currently only tests the case where the DUT is a playback device and the
System Audio device is a TV, because the CEC client responds <Feature
Abort> to <Set Audio Volume Level> if it is started as an audio system.

Bug: 199144624
Test: tools/cts-tradefed run cts -m CtsHdmiCecHostTestCases -t android.hdmicec.cts.playback.HdmiCecAvcToTvTest
Change-Id: I9aec9682db7f331380facacf954fbbd62c8d8695
7 files changed