CTS: Skip tests that cause volume keyevents for certain setup

When testing with HDMI stub instead of TV, the device used by
"STREAM_MUSIC" might be internal speaker instead of HDMI_OUT.
This could cause these two tests to fail as audio service will
not announce HdmiControlService about the volume change upon
calling adjustStreamVolume/setStreamVolume.

Bug: b/386151355
Test: atest android.hdmicec.cts.playback.HdmiCecAvbToTvTest
Flag: EXEMPT Bugfix only
(cherry picked from https://googleplex-android-review.googlesource.com/q/commit:c64f9d9c7c0e5e8e630aeb84d8047410fa0339ec)
Merged-In: I703a0a7b194dca7ff22c325ea00393ac5dc03fce
Change-Id: I703a0a7b194dca7ff22c325ea00393ac5dc03fce